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Optoelectronic Neural Interfaces Based on Quantum Dots
- Mertcan Han
Mertcan HanDepartment of Electrical and Electronics Engineering, Koç University, Istanbul 34450, TurkeyMore by Mertcan Han
- ,
- Onuralp Karatum
Onuralp KaratumDepartment of Electrical and Electronics Engineering, Koç University, Istanbul 34450, TurkeyMore by Onuralp Karatum
- , and
- Sedat Nizamoglu*
Sedat Nizamoglu*Email: [email protected]Department of Electrical and Electronics Engineering, Koç University, Istanbul 34450, TurkeyGraduate School of Biomedical Science and Engineering, Koç University, Istanbul 34450, TurkeyMore by Sedat Nizamoglu
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Abstract
Optoelectronic modulation of neural activity is an emerging field for the investigation of neural circuits and the development of neural therapeutics. Among a wide variety of nanomaterials, colloidal quantum dots provide unique optoelectronic features for neural interfaces such as sensitive tuning of electron and hole energy levels via the quantum confinement effect, controlling the carrier localization via band alignment, and engineering the surface by shell growth and ligand engineering. Even though colloidal quantum dots have been frontier nanomaterials for solar energy harvesting and lighting, their application to optoelectronic neural interfaces has remained below their significant potential. However, this potential has recently gained attention with the rise of bioelectronic medicine. In this review, we unravel the fundamentals of quantum-dot-based optoelectronic biointerfaces and discuss their neuromodulation mechanisms starting from the quantum dot level up to electrode–electrolyte interactions and stimulation of neurons with their physiological pathways. We conclude the review by proposing new strategies and possible perspectives toward nanodevices for the optoelectronic stimulation of neural tissue by utilizing the exceptional nanoscale properties of colloidal quantum dots.
This publication is licensed under
CC-BY 4.0.
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Attribution (BY): Credit must be given to the creator.
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License Summary*
You are free to share (copy and redistribute) this article in any medium or format and to adapt (remix, transform, and build upon) the material for any purpose, even commercially within the parameters below:
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Attribution (BY): Credit must be given to the creator.
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License Summary*
You are free to share (copy and redistribute) this article in any medium or format and to adapt (remix, transform, and build upon) the material for any purpose, even commercially within the parameters below:
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1. Introduction
ARTICLE SECTIONS
Neural interfaces offer modulation of cellular signals to understand complex neural circuits and treat various disorders including cardiac problems, (1) paralysis, (2) epilepsy, (3) Parkinson’s disease, (4) and other neurological disorders. (5−7) The advent of nanotechnology enabled ultrasmall building blocks for neural interfaces with advanced functions that can simultaneously enable efficient, injectable, biocompatible, capacitive, soft and flexible neural interfaces, which can overcome the limitations of their bulky counterparts. Among a wide variety of nanomaterials, colloidal quantum dots (QDs) have exceptional properties such as comparable size with the cell membrane (i.e., 8–10 nm), (8) ultrasensitive tunability of electronic energy levels via the quantum confinement effect (i.e., size effect), and near-unity quantum efficiency. (9,10) Because of these favorable optoelectronic properties, QDs have been widely used in a wide range of optoelectronic devices such as light-emitting diodes (LEDs), (11) photodiodes, (12,13) solar cells, (14,15) and phototransistors. (16) More interestingly, they can be conjugated with a wide variety of biomolecules targeting membrane proteins/receptors with QD–antibody or QD–ligand conjugates for biolabeling, (17,18) bioimaging, (19−21) targeted drug delivery or cancer treatment, (21) biosensing, (22,23) and neural stimulation (Figure 1). Therefore, colloidal quantum dots hold high promise for future bioelectronic medicine for neurological diseases.
Figure 1
Figure 1. Applications of semiconductor quantum dots for neurotechnology (top). Schematics for the three main configurations that can lead to neural stimulation using quantum dots (bottom). The free-standing configuration represents the interaction between the targeted cells and the QDs in the extracellular medium without any physical, chemical, or biological attachment to the cell membrane. The second configuration (bottom middle) exhibits the interaction between the targeted cells and the QDs, which may bind to the cell membrane through QD–antibody conjugates or via conjugation with target specific ligands, such as peptides and proteins. The third configuration (bottom right) utilizes QDs in thin-film or blend form. Neuron–QD interaction depends on the chemical, physical, or ionic stimuli generated by QDs.
Toward the cellular stimulation goal, QDs operate with the fundamental mechanism of transduction of light to controlled ionic currents for optical control of neurons. Optogenetics, the frontier method for light-triggered control of neural circuits, induces nanoscale photosensitive ion channels in the membrane by permanent genetic modification of the natural structure of the membrane by using a viral vector. However, gene delivery and manipulation methods require a high level of refinement to adapt them for gene-specific conditions (24) and there are also ethical concerns on the safety of gene therapy for clinical practice. (25) As a nongenetic approach, today silicon (26,27) and semiconductor polymers (28) offer effective optoelectronic material options to control light-triggered modulation of neurons in vitro and in vivo, (29) which showed promise in cellular stimulation and recovery of vision against blindness at the clinical level. (30) However, the low absorption coefficient of silicon (383 cm–1 at 880 nm) (31) necessitates the formation of substrates for neural interfaces that are tens of micrometers thick, resulting in rigid devices with high Young’s modulus values in the megapascal and gigapascal range. The mechanical mismatch between the biological tissue and rigid biointerfaces may lead to scar tissue formation as well as the foreign body response, which reduces device performance and functional lifetime for these devices. (32) On the other hand, quantum dots, which have absorption coefficients that are orders of magnitude higher than that of silicon, can enable ultrathin and flexible devices on silk, poly(ethylene terephthalate) (PET), polydimethylsiloxane (PDMS), and parylene and can be potentially integrated with low Young’s modulus conductive materials such as poly(3,4-ethylenedioxythiophene) polystyrenesulfonate PEDOT:PSS and its hydrogel for tissue-like interfacing with neurons. (33,34) Furthermore, they may even operate at a single colloid level for the control of neural activity. QDs are also recognized for their outstanding optical stability, showing very little photobleaching or chemical degradation compared to organic dyes. (35) Approved by the millions of units sold QLED TVs, they can be synthesized at large scales with low cost and combined with solution-processable fabrication techniques that can pave the way toward a widely usable and economically feasible neural prostheses. Therefore, these features make QDs a promising alternative for optoelectronic neural interfaces.
This review discusses the fundamentals and potential of QD-based optoelectronic biointerfaces (Figure 1) converting optical energy to ionic electrical currents to modulate cellular processes, particularly to stimulate neurons. First, the physical mechanisms of QD integrated neural interfaces and dominant biophysical mechanisms of optoelectronic stimulation are discussed. Next, we summarize pioneering studies as well as recent advances for several types of QD optoelectronic neural interfaces while discussing the biocompatibility of such devices. Finally, we discuss future perspectives and new opportunities for future QD integrated optoelectronic biointerfaces. Different from the previous reviews, (26,36−45) we focus here on state-of-the-art applications for neural interfaces using quantum dots.
2. Properties and Neuro-interfacing Configurations of Quantum Dots
ARTICLE SECTIONS
The interest in quantum dots began with the discovery of quantum size effects in the semiconductor nanocrystals (NC). The synthesis of the first quantum dots in a dielectric glass matrix was followed by their colloidal synthesis in a liquid medium. Moreover, the theoretical studies aimed to model and understand the charge carrier behavior in quantum-confined crystal structures. (46−51) Now, it is well-known that the squeezing of excitons in quantum dots leads to size-dependent electronic and optical properties (Figure 2a), which makes them attractive materials for various applications such as light-emitting diodes, lasers, solar cells, luminescent solar concentrators, biomarkers, and biolabels. (17,52−54)
Figure 2
Figure 2. (a) Quantum dots with stepping emission from blue to red (top). Representative photoluminescence spectrum for different size quantum dots (middle). Representative conduction and valence band diagram for different sizes of semiconductor quantum dots (bottom). (b) Representative TEM images for core/shell quantum dots (scale bars: 20 and 5 nm, respectively). (c) Core/shell semiconductor nanoparticle systems with type I, quasi-type II, and type II band alignment.
Optoelectronic properties of quantum dots were progressively improved via advancements in the field of nanochemistry. Novel synthesis methods resulted in “high-quality” nanocrystals that have near-unity photoluminescence quantum yield (PLQY), narrow emission line widths, sharp absorption profiles, and atomic-level size tunability. (55−57) For that, production of core/shell nanostructures (Figure 2b), where a small bandgap core nanocrystal is covered with a larger bandgap shell material, (58) is an effective approach to engineer electronic and optical properties of QDs. Shell growth renders superior surface properties to QDs because of the passivation of surface trap states and tunable energy levels, leading to enhanced optoelectronic characteristics and optical and chemical stability. (58,59)
Depending on the electronic energy level alignment between the core and shell materials in a core/shell QD nanostructure, QDs are categorized into different types (Figure 2c). In type I QDs (e.g., CdSe/CdS, CdSe/ZnS QDs), shell material has a higher conduction band and lower valence band energies compared to the core material, which results in the confinement of electrons and holes in the core with high exciton binding energies. On the contrary, in type II QDs (e.g., CdS/ZnSe, CdTe/CdSe, InP/ZnO QDs), one type of charge carrier localizes in the core, whereas the other charge carrier moves to the shell because of the favorable conduction or valence band energy level of the shell. Moreover, the quasi-type II QD band structure exhibits only partial delocalization of one charge carrier to the shell (Figure 2c). Compared to type I QDs, the exciton binding energies of type II QDs are lower because of the increased physical distance that causes reduced Coulombic force between the bound electrons and holes. (60) Besides, the increased distance between electron and hole leads to reduced radiative recombination rates and increased recombination lifetimes in type II or quasi-type II QDs. (61) The increased fluorescence lifetime enables the detection of time-gated signals to monitor cellular behavior. (20) Likewise, the increase in recombination lifetime is beneficial for charge carrier interactions and transfer to the neighboring materials.
One notable recently emerged application of QDs is neural interfaces. Being efficient absorbers in the visible to near-IR spectrum, QDs are promising materials for photoactive neural interfaces. (62) QDs can be functionalized to couple them directly with the cell membrane within only nanometer-scale distances using certain antibodies or peptides. (20,63) For example, avidin-conjugated QDs have been utilized for cell labeling and imaging by attaching through the biotin, the affinity pair of avidin. (64,65) Moreover, the excitation of QDs can potentially alter the membrane potential due to the electric field generated by the electron–hole separation in the excited QDs. For QDs, there are three possible configurations for cellular stimulation (Figure 1 bottom): (i) free-standing interaction in the extracellular medium with cells, (ii) direct interaction with cellular attachment using surface functionalization, and (iii) integration of QDs into photovoltaic devices either as the photoactive material or electron/hole transport layer. Stimulation of neurons via free-standing configuration has not been achieved yet, possibly because of the strong decay of the electric field generated by the QDs. Because the extracellular medium hosts polarized ions and mobile charge carriers, the screening effect can dampen the generated electric field. Moreover, because the voltage-gated ion channels require at least a 5–10 mV potential difference for switching, (40) the effective stimulation distance is even shorter than the effective electric field volume. Therefore, the first configuration requires high concentration of QDs that can allow high number of QDs to be near cells. However, the possible cytotoxicity of the concentration effect needs to be considered. The second configuration is convenient to specifically bind QDs to targeted cells without increasing the loading concentration in the extracellular medium to overcome this problem. The advances in bioconjugation schemes and QD surface functionalization have already been proven for bioimaging and targeted treatments using peptide-coated, avidin-coated, and many other techniques. (20) The same Debye length limitation also applies for the second configuration, but close-proximity operation can potentially enable stimulation of neurons while having acceptable QD on the membrane densities. (22,66)
On the other hand, layered photovoltaic architectures with QDs, such as in Figure 3, have exhibited more convenient fabrication procedures and promising results in comparison with the other configurations. Solid films of QDs can effectively convert light energy into ion-based electrical current (photocurrent) in electrolytes, which can achieve extracellular stimulation of nearby neurons. Indeed, this photoelectrical stimulation route using QD films was proven to be effective with few early pioneering studies. (67,68) Later, inspired from QD-based solar cell devices combined with a bioelectrical perspective, the ability to integrate QD films into various device architectures (e.g., combining QDs with electron and/or hole transport materials, heterojunctions of QDs with semiconducting organic polymers) while considering the device-electrolyte interactions led to advanced quantum dot opto-bioelectronic devices for the optical control of neurons. (69−71)
Figure 3
Figure 3. (a) Schematic diagram of a generic photovoltaic biointerface architecture. (b) Energy band diagram of a regular (top) and inverted optoelectronic system (bottom). The layers represent the corresponding layers in panel a. The exciton generation occurs in the active layer upon illumination. Dissociated electron and the hole move toward the charge transport layers according to the energy levels between the layers.
3. Physical and Physiological Mechanisms of Neural Interfaces
ARTICLE SECTIONS
3.1. Physical Mechanism, Device Design, and Operation Principles
The first process occurring during the operation of QD-based optoelectronic biointerfaces is photon absorption. The absorption of impinging light is dependent on the energy of the incoming photons and bandgap of the QDs in the device structure that can be controlled by the size of the QD. Because of the size-tunability of QDs, highly tunable absorption edges ranging from visible spectrum (e.g., by using CdSe, InP) up to near-IR (e.g., by using PbS) can be built. QDs can manifest linear or nonlinear absorption characteristics by single photon or multiphoton absorption processes, respectively. (72) This can affect the dependency of the photoresponse of the biointerfaces to the illumination intensity. Biointerfaces operating via single photon absorption demonstrate linear light intensity-photocurrent relationship, whereas multiphoton absorption would result in nonlinear (quadratic or higher) dependency of photocurrent to light intensity. (67)
Upon absorption, electron–hole pairs are created in the QDs. These charge pairs are in a bound state with a binding energy due to the Coulombic attraction between them. QDs exhibit rather large exciton binding energies compared to the thermal energy at room temperature. (61) One strategy to stimulate neurons is to use the dipole electric field created by the bound excitons. (73) If neurons are placed sufficiently close to the QDs, the electric field produced by the photogenerated bound excitons can alter the transmembrane potential and evoke action potentials if the induced affect is large enough. Indeed, it was theoretically shown by Winter et al. (73) that the dipole strengths around the reported values of 30 D for QDs (74) can generate electric potentials greater than 15 mV at a distance of 10 nm in deionized water, which would be sufficient for the opening of voltage gated ion channels, leading to action potential firing. (75) However, in an ionic medium similar to the extracellular environment of neurons, the distance for observing the same effect reduces to approximately ∼2 nm due to electric field screening in an ionic medium. (73) The maximum distance even decreases below that due to the additional structures on the cell membrane (e.g., antibodies) and QDs (e.g., ligands), which may induce further screening effects. (68) It must be noted that these numbers correspond to the effect of a single nanocrystal. In case of a favorable alignment of many nanocrystals, the collective impact of QDs can be much more pronounced. Yet, despite achieving the coupling of QDs as close as 3 nm to the cell membrane, (63) photoexcitation of neurons with this strategy was still not achieved.
QD films in photovoltaic biointerface architectures provide a versatile platform for photostimulation. QD films have been widely used in photovoltaic systems as photoactive layer for converting light into electron–hole pairs and photon downshifting layer for converting higher energy photons into lower energy photons. (76,77) Tight packing of nanocrystals leads to increased charge transportation rates between QDs due to the decreased interparticle distance and thus higher conductivity. (61,78) Their charge transport properties can be further enhanced via ligand exchange and thermal treatments. (79,80) In general, the studies demonstrating the successful photoexcitation of neurons have utilized QD solid films that are either coated on a transparent electrode (e.g., ITO) or together with charge transport layers (Figure 3a). (67−69) Because of the band alignment in device architecture, the photogenerated charges are dissociated (Figure 3b), and one type of charge is accumulated on the biointerface-electrolyte interface where neurons are positioned. The charge accumulation on the interface generates photocurrent in the electrolyte via capacitive and/or faradaic processes, which then depolarizes or hyperpolarizes the neural membrane potential depending on the direction of the photocurrent and the type of the ion channels that are activated. (67−69)
Electron and hole localization within QD heterostructure influences the performance and/or charge injection mechanism of the QD-based biointerfaces. Remarkably, the carrier localization in QDs can be tuned by proper choice of core and shell materials. The conduction and valence band energy alignment of core and shell materials lead to formation of type I, quasi-type II, or type II QDs that can directly control the electron and hole wave functions, i.e., the spatial separation of electron–hole pairs (Figure 2c). (81) Moreover, while keeping the heterojunction the same, the thickness of the shell also influences the carrier localization that shifts the oscillator strength of electronic transitions and thus the absorption profile. (82) For neural interfaces, this nanoengineering ability at the single nanomaterial level is unique in comparison with their polymeric and metallic counterparts. For example, the photocurrent generation by a QD-based neural interface was shown to be enhanced when a type I QD (InP core) was replaced with its type II counterpart (InP/ZnO) in the same device architecture. (69) One of the main factors leading this improvement was reduced electron–hole wave function overlap, which facilitates more effective charge transfer to the nearby electron acceptor layer due to increased spatial separation of charges in type II QD and reduced surface defects (Figure 4a). This ability (Figure 4b) provides a promising route for tuning the contribution of capacitive and faradaic charge injection processes at the device-electrolyte interface as well (Figure 10e, f). (83)
Figure 4
Figure 4. Quantum mechanical simulations of type I and type II nanocrystals, showing the effect of wave function engineering on charge carrier localization. (a) Top: Blue lines show energy band alignment and black lines show minimum electron and hole discrete energy levels. R and R+H correspond to the radius of the InP core and the InP/ZnO core/shell QDs, respectively. Bottom: Simulated electron and hole wave functions for the InP core (top) and the InP/ZnO core/shell (bottom) QDs. Black and red lines show electron and hole radial probability functions, respectively. Blue line represents the electron confinement potential. Dashed black and red lines represent single electron and hole energies, respectively. Reprinted with permission from ref (69). Copyright 2018 American Chemical Society. (b) Top: Energy band alignment schematics of type I InP/ZnS and type II InP/ZnO/ZnS QDs. Bottom: Simulated electron (red lines) and hole (black lines) wave functions for InP core, InP/ZnS core/shell, and InP/ZnO/ZnS core/shell/shell nanocrystals. Blue lines represent the electron confinement potential. Reprinted with permission from ref (83). Copyright 2021 Springer Nature. In both studies, type II nanostructures exhibit electron delocalization to shells, which leads to decreased electron–hole wave function overlap, i.e., reduced exciton binding energy.
3.2. Biophysical Mechanisms for Modulating Neural Activity
In a QD-based neural interface, the photogenerated electrons or holes that accumulate close to the electrode/electrolyte interface induce electrochemical processes in the aqueous cellular environment. Those processes perturb the distribution of ions such as sodium, potassium, and chloride near the neural membrane, which leads to activation or suppression of neural activity. Depending on the interfacial impedance, one of the two primary charge injection mechanisms, faradaic or capacitive, take place at the electrode–electrolyte interface. These two mechanisms are illustrated in Figure 5a. In most cases, however, interfacial impedance involves both a double layer capacitance, a charge transfer resistance, and a Warburg impedance representing the diffusion processes in the presence of reversible reactions. Thus, a simple electrical circuit model consisting of a capacitor and a resistor can be used to model the electrode–electrolyte interface (Figure 5b).
Figure 5
Figure 5. Primary charge injection mechanisms in QD-based biointerfaces. (a) Illustration of faradaic and capacitive charge injection mechanisms. Electrons or holes accumulate on the biointerface surface, inducing faradaic or capacitive charge injection in the electrolyte (hole accumulation was shown as a representative case). IHP, inner Helmholtz layer, OHP, outer Helmholtz layer, GCL, Gouy–Chapman diffuse-charge layer. (b) Electrical circuit model of the electrode–electrolyte interface. Cdl represents double-layer capacitance and is equivalent to the series sum of IHP, OHP, and GCL capacitances. RCT and Rs denotes charge transfer resistance and solution resistance, respectively. W represents Warburg impedance. (c) Typical current–voltage profiles of resistive and capacitive elements.
3.2.1. Faradaic Stimulation
The faradaic charge injection mechanism involves electron exchange between the neural interface and the electrolyte (Figure 5a). Charge transfer can take place in both ways, i.e., by injecting electrons into or extracting electrons from the electrolyte. Electron transfers at the electrode–electrolyte interfaces can lead to a wide variety of faradaic reactions. For example, electron injection into the electrolyte can cause reduction reactions (e.g., reactive oxygen species (ROS) generation), whereas electron removal from the electrolyte can lead to oxidation reactions. Thus, the direction of photocurrent gives information on the possible faradaic reactions occurring at the device–electrolyte interface. The occurrence of electron transfer between a neural interface and electrolyte depends mainly on two conditions. First, there should be a favorable energy state for electrons to move in the electrolyte. Second, the electric potential at the device/electrolyte interface should be in the range that is required for the occurrence of electron transfer reaction (e.g., see the review by Kumsa et al. for the detailed description of electron transfer processes between a stimulation electrode and electrolyte). (84) When both conditions are satisfied and reactants are present at the electrode/electrolyte interface, reversible or irreversible faradaic reactions can arise.
In irreversible faradaic processes, the reaction product moves away from the reaction site faster than the electron transfer rate, meaning there is no charge storage at the interface and the reaction products cannot be reversed back to their reactant form. (85) The unrecovered products diffusing into the electrolyte alter the physiochemical properties of the environment, posing potentially harmful effects to both neurons and biointerface. In this case, the dominant charge injection process is resistive, and the interfacial current–voltage (IV) profile in an ideal case, where double layer capacitor is negligible, can be represented with a resistor IV shown in Figure 5c.
Reversible faradaic reactions have much faster electron transfer rates compared to irreversible processes. Because the reaction products move away from the reaction site at a slower rate compared to the electron transfer rate, there is a charge storage in the interface in reversible faradaic reactions. Because of the closeness of reaction products to the interface, the products can be recovered back to their initial reactant form if the polarity of the electric potential is reversed. (85) In an ideal case where the charge transfer resistance is infinite, this results in an IV profile of a capacitor at the electrode–electrolyte interface (Figure 5c).
Although the reduction oxidation processes occurring at the electrode–electrolyte interface have been studied for conventional electrodes like Au and Pt, (86,87) redox processes at the QD–aCSF (or PBS) interface have not been elucidated yet. Dye-sensitized solar cells (DSSCs) are more mature technology with a similar operation principle to QD-based biointerfaces in the sense that they both operate in an electrochemical medium. However, the electrolytes used in DSSCs are different than aCSF or PBS. One recent study investigated the possible faradaic reactions occurring at InP QD-based biointerface-aCSF interface. (88) The followed strategy was to investigate the photocurrent response of the biointerfaces in modified aCSF solutions, each is deficient of one constituent, to understand the faradaic processes according to the changes in the photocurrent in response to the removal of a constituent. This showed that the oxidation reactions at the QD–aCSF interface involve reactions with HEPES and water, while the reduction reactions are mostly occurring with water. (88) Another possible strategy for identifying the faradaic processes could be the cyclic voltammetry (CV) analysis of QD biointerfaces in solutions of the constituent materials of aCSF or PBS. (87) The resistive-like behaviors in CV measurements indicate the presence of faradaic reactions, and the corresponding potential values would enable identification of oxidized or reduced constituent.
3.2.2. Capacitive Stimulation
When there is no net charge transfer between a neural interface and the electrolyte, photocurrent can be generated by redistribution of ions in the extracellular medium. Upon illumination of a QD-based biointerface, one type of charge carrier accumulates on the surface of the device, causing a change in the net charge of the surface. This induces the movement of oppositely charged ions close to the surface and similarly charged ions away from the surface, leading to formation of a double layer capacitor in the device/electrolyte interface. The double layer consists of three different layers, the inner Helmholtz plane (IHP), the outer Helmholtz plane (OHP), and the diffuse charge layer (Figure 5a). IHP is formed by adsorbed ions onto the surface and preferentially oriented water molecules forming a hydration sheath. The OHP mostly contains solvated ions that are not able to penetrate the hydration sheath. Finally, the diffuse layer contains both solvated and unsolvated ions whose density decreases with the distance from the electrode–electrolyte interface. Hence, the total double layer capacitance (Cdl in Figure 5b) is composed of serially connected IHP, OHP, and diffuse layer capacitances. (89) Ideally, pure capacitive electrodes have infinite charge transfer resistance (RCT in Figure 5b), meaning that the charge transfer rate is zero at the electrode–electrolyte interface and all current flows through the double layer capacitor as displacement current, which leads to a capacitor IV profile at the interface (Figure 5c).
Because capacitive stimulation involves a reversible charging/discharging process and does not cause electron exchange between the device and electrolyte, the physiochemical properties of the electrolyte such as electroneutrality and pH are preserved. This renders capacitive charge injection mechanism as a safer alternative to irreversible faradaic processes, which motivates researchers to introduce viable methods for tuning the capacitive and faradaic components of the injected charge to minimize the faradaic and maximize the capacitive charge injection.
3.2.3. QD Biointerface Design for Controlling the Charge Injection Mechanism
Because of the reversibility and biocompatibility of capacitive charge injection mechanism, different strategies were proposed to minimize the faradaic processes in QD-based neural interfaces to generate a capacitive-dominant photoresponse. Inspired from donor–acceptor bulk heterojunctions used in organic solar cells, QDs were used as a donor material in a QD–fullerene nanoheterojunction structure to produce capacitive-dominant photocurrents in an extracellular medium. (83) QD–fullerene donor–acceptor structure separates the photogenerated electron–hole pairs, whereas the ZnO layer in the device architecture facilitates further separation by providing high mobility to electrons (Figure 6a, b). In addition, to minimize the electron transfer between the surface traps and electrolyte (Figure 6c), the PLQY of the QDs was kept high, which is an indication of successful surface passivation. (85) Another study demonstrated the control of faradaic and capacitive processes to the photoresponse of a biointerface by engineering the electronic band alignment of the device without surface modification. (71) Proper manipulation of the band alignment enables controlling the type of charge carrier (electron or hole) that will be accumulated on the electrolyte interface (Figure 6d, e). If the energy level of the charge carrier accumulated on the surface is not favorable for involving in faradaic reactions, then the electron transfer between the biointerface and electrolyte is minimized. The accumulated charge carrier then induces capacitive photocurrent by charging/discharging of the double layer formed at the interface. (71)
Figure 6
Figure 6. Obtaining capacitive-dominant QD-based biointerfaces via donor–acceptor nanoheterojunction (a–c) and band alignment engineering (d, e). (a) Device structure of QD-fullerene donor–acceptor nanoheterojunction-based interfaces for obtaining capacitive-dominant photoresponse. (b) Schematic showing the electron transfer from QD to fullerene derivative PCBM upon photoexcitation. (c) Capacitive photocurrent generation mechanism showing each step in a consecutive manner. Eb, exciton binding energy; Ecb, Evb, Ess, conduction band, valence band, and surface state energy levels, respectively. Band bending at the electrolyte interface prevents electron transfer to electrolyte. Electrons will then be transferred to ZnO and ITO because of the high electron mobility of ZnO. Holes are trapped in the QD valence band because of the ZnO valence band level, which induces capacitive photocurrent. Panels a, b, and c reprinted with permission from ref (83). Copyright 2021 Springer Nature. (d) Schematic of device architecture containing photoactive layers of P3HT:PbS:PCBM, with the intermediate layer (ZnO, MoOx, or none) coated on glass/ITO substrates. Although the photoactive layer generates excitons within the device, the energy level of the intermediate layer determines the surface polarity by routing either the electrons or the holes toward the top surface layer. (e) Manipulation of the band alignment via choice of different intermediate layers. Type I and type II devices generate faradaic-dominant photocurrents due to electron transfer from the PCBM LUMO level to electrolyte. Type III architecture accumulates holes on the surface. Holes do not interact with the electrolyte because of the unfavorable energy level of P3HT HOMO and water oxidation levels, which leads to capacitive-dominant photoresponse. Panels d and e reprinted with permission from ref (71). Copyright 2018 American Physical Society.
So far, all the reported QD-based biointerfaces are optoelectronic devices, i.e., they transduce electromagnetic energy into electrochemical current through photocapacitive or photofaradaic mechanisms, thereby electrically stimulating neurons. Light can also be converted into thermal or acoustic energy via photothermal and photoacoustic effects to modulate the neural activity. Absorption of light can trigger lattice vibrations in a crystal structure as a result of nonradiative phonon processes. These vibrations generate local transient heat, which can evoke action potentials by opening thermosensitive ion channels (90) or causing capacitive membrane currents. (91) Alternatively, the induced transient heat upon photoexcitation can cause acoustic wave generation by thermoelastic expansion and contraction of molecules in the photoexcited region, which can mechanically stimulate neurons. (92) Different material types such as silicon, (93) metallic nanoparticles, (94) graphene, (95) and organic polymers (96) showed promise for utilizing photothermal effect for building effective neurostimulation systems. The use of photoacoustic effect for neurostimulation was more recently introduced and reported in only a few studies so far. (97,98) Such alternative stimulation mechanisms can be exploited by next-generation QD-based biointerfaces to design alternative systems involving QDs in transducing optical energy into thermal and acoustic energies. (99,100)
To date, optoelectronic QD–biointerfaces have used different II–VI and III–V semiconductors such as mercury telluride (HgTe), cadmium selenide (CdSe), indium phosphide (InP), lead sulfide (PbS), and aluminum antimonide (AlSb), which are summarized in Table 1. In the next section, we examine all these structures in detail, compare their disadvantages and advantages, and draw a perspective for future studies.
Table 1. Examples of Semiconductor Nanoparticle-Based Optoelectronic Neural Interfacesa
| nanoparticle | interface type | dominant charge generation | modulation effect | operational illumination intensity (mW cm–2) | responsivity (mA/W) | cell type | transmembrane potential change (mV) | refs |
|---|---|---|---|---|---|---|---|---|
| HgTe | multilayered | capacitive | excitatory | 800 | N/A | NG108 | +10 | (67) |
| ITO/(PDDA/HgTe)N | faradaic | |||||||
| CdSe | single-layer | N/A | excitatory | 0.46 | N/A | LnCap | +13 | (68) |
| CdTe | CdSe and CdTe QD films | N/A | inhibitory | –4 | ||||
| CdSe/CdS | multilayered | (113) | ||||||
| CNT CdSe/CdS | capacitive | excitatory | 30 | 0.6 | embryonic chick retinas, E14 | N/A | ||
| InP/ZnO | multilayered | excitatory | 0.40 | N/A | PC12 | +45 | (69) | |
| ITO/ZnO/InP//ZnO QD | faradaic | |||||||
| InP/ZnS | multilayered | excitatory | 57 | 2.3 | PHN | +110 | (88) | |
| ITO/InP//ZnS QD/ZnO | faradaic | inhibitory | 7.5 | –45.6 | ||||
| ITO/TiO2/InP//ZnS QD | ||||||||
| InP/ZnO/ZnS | multilayered | N/A | 57 | 0.8 | N/A | N/A | (83) | |
| ITO/ZnO/PBCM:InP/ZnO QD | capacitive | |||||||
| InP/ZnS QF | multilayered | excitatory | 169 | N/A | SH-SY5Y | +1.21 | (70) | |
| ITO/TiO2/InP//ZnO QDs | faradaic | |||||||
| PbS | multilayered | excitatory | 1 | N/A | SH-SY5Y | +4.7 | (71) | |
| ITO/P3HT:PbS QD:PCBM | faradaic | |||||||
| ITO/MoOx/P3HT:PbS QD:PCBM | faradaic | |||||||
| ITO/ZnO/P3HT:PbS QD:PCBM | capacitive | |||||||
| PbS | multilayered | excitatory | 1 | 99 | PHN | +70 | (101) | |
| ITO/ZnO/P3HT:PbS QD:PCBM | capacitive | |||||||
| AlSb | multilayered | excitatory | 100 | 6 | PHN | +103 | (102) | |
| ITO/ZnO/P3HT/AlSb QD | capacitive |
a
/ indicates layer-by-layer coating, whereas // indicates core/shell QD structures.
4. Quantum Dot Systems for Neural Stimulation
ARTICLE SECTIONS
4.1. HgTe QD-Based Neural Interfaces
During the rise of colloidal quantum dots in the 1990s, superior properties such as high sensitivity and responsivity of QDs have been utilized by scalable production techniques in several optoelectronic devices. Among them, HgTe QDs took particular attention as a narrow semimetal absorber and they were widely studied for photodetectors. (103−105) The pioneering work of Kotov and his co-workers (67) demonstrated the first photostimulation of neurons by using QDs, for which HgTe QD was used. The whole device structure with HgTe and PDDA layers was fabricated via layer-by-layer (LBL) on conductive ITO-coated glass substrates, where the ITO layer supplies electrons to the system (Figure 7a). HgTe QDs were stabilized with thioglycolic acid for surface passivation and coated with poly(dimethyldiallylammonium chloride) (PDDA) as a positively charged partner of the HgTe QDs (Figure 7a). (67)
Figure 7
Figure 7. Pioneering semiconductor nanoparticle-based optoelectronic neural interfaces. (a) HgTe QDs stabilized with thioglycolic acid-coated single-material device. (b) Light absorption characteristics (1, solid line) and photogenerated voltage (2, bars) of HgTe QDs and layer-by-layer films. UV–vis absorption spectrum on HgTe QD dispersion stabilized by thioglycerol used for fabrication of LBL films. (c) Action potential responses of NG108 cells grown on (PDDA/HgTe)12 + (PDDA/Clay)2 under photostimulus with and without tetrodotoxin (TTX). Panels a, b, and c reprinted with permission from ref (67). Copyright 2007 American Chemcial Society. (d) Schematic of the interaction between a QD and cell membrane. (e) UV–visible absorbance and photoluminescence (PL) characterization of CdTe QDs. (f) Current-clamped recording of cortical neurons on CdSe QD film. Fluorescence image of a micropipette coated with CdSe QDs used for single-cell stimulation. Panels d, e, and f reprinted with permission from ref (68). Copyright 2012 The Optical Society. (g) Schematic of the optoelectronic coupling between NR-conjugated CNT coated by ppAA. (h) Schematic drawing of the CdSe–GSH QDs (left), CdSe/CdS–GSH QDs (center), and CdSe/CdS–GSH NRs (right). Average photocurrents for different devices based on CdSe, CdSe/CdS, and CdSe/CdS NRs with CNTs under an excitation pulse of 30 mW cm–2 for 100 ms with a 405 nm illumination source. (i) (Upper left) SEM image of an NR–CNT film (scale bar: 100 nm). (Upper right) CNT electrode array on a PDMS flexible support (scale bar: 1 mm). (Bottom) Extracellular voltage trace recorded from a chick retina following 100 ms light stimulation (405 nm, pulse interval of 30 ms) under different intensities (1.2, 3, 6, and 12 mW cm–2). Panels g, h, and I reprinted with permission from ref (113). Copyright 2014 American Chemical Society
Upon excitation with visible illumination (Figure 7b), the photogenerated excitons in the HgTe layer show a single photon absorption process since the photocurrent increases linearly with the increasing illumination intensity. The origin of photocurrent is attributed to the photoinduced electron transfer between the HgTe QD layer and O2 because the HgTe QD conduction band is at −4.6 eV and O2 acceptor energy level is at −5.3 eV. Moreover, the biphasic behavior of the photocurrent transient indicates a capacitive pathway due to separate charging and discharging peaks. To evaluate the biological response, we chose neuroblastoma-glioma cell line NG108 as the model cell line, which benefits from being more resistant to environmental changes. As a solution for providing a biocompatible and adhesive layer for cell attachment against the toxic-heavy-metal Hg content, polylysine/poly(acrylic acid)/polylysine (PLP) was adopted as the interfacial layer. The membrane potential of cells were recorded with a patch-clamp system, which enables the measurement at the single-cell level, and successful stimulation of cells was observed (Figure 7c). In some of the coupled individual cells, 10 mV depolarization was observed while the mean depolarization was 2.3 ± 2.4 mV due to coupling issues between the cells and the biointerface. The membrane depolarization levels after several stimulations showed minimal membrane resistance change, indicating safe stimulation without thermal or direct light gating effects. To support these biocompatibility signs, we also added LBL films of clay sheets as the interfacial layer. Although clay enabled capacitive currents, during the electrophysiology experiments, faradaic (resistive) coupling with cells was interestingly observed. This pioneering study opened a new direction of research by using QDs for modulation of the electrical activity of cells, and the results also point out the requirement of biocompatible and capacitive neural interfaces for cell stimulation.
4.2. Cd-Based QD Neural Interfaces
After the initial study on the HgTe QD-based biointerface, the work by Lugo et al. (68) suggested a new theoretical framework based on the near-field electromagnetic wave and membrane coupling. They proposed the electric dipole moment created by the electron–hole separation in the excited QD with the membrane potential change (Figure 7d). The relation between the QD-induced electric field and membrane proximity can be regarded as a superposition of each electron–hole pair generated by the QDs. (68) Considering the Debye length of the saline, the electric field potential may drop exponentially with the distance between the QDs and the cell membrane. Motivated by combining this theoretical framework with experimental results, they have used multilayer QD films, specifically CdTe and CdSe films, without any other mediator layer. Cd-based QDs were already widely used in fluorescent imaging studies in vivo (106,107) and biological labeling in vitro (108−111) because of their strong absorption and emission in the visible spectrum (Figure 7e). Electrophysiology experiments on cultured prostate cancer (LnCap) cells on CdTe QD films and cultured cortical neurons on CdSe QD films showed promising results. Under 430 nm with 1 × 107 photons μm–2 s–1 illumination, an equivalent of 462 μW cm–2, CdTe QD films induced membrane hyperpolarization, which is attributed to the activation of potassium channels in prostate cancer cells. (112) Moreover, the cells that are 20–30 μm above the CdTe QD film were not affected by the electric field because of the exponential decay of the field with distance. The optoelectronic characterization, particularly photocurrent measurements without the seeded cells, would be useful to distinguish any contribution by the Faradaic reactions. Second, CdSe QD films were tested with cortical neurons under 550 nm illumination with the same intensity. The excitation of the QD films led to membrane depolarization and evoked multiple action potentials (Figure 7f). However, in both studies, there were temporal and spatial variations in the stimulation performance. This interesting study suggested an alternative mechanism to modulate membrane potential via QDs.
To improve the optoelectronic performance of biointerfaces, Hanein and her co-workers combined two nanomaterial systems, namely, semiconductor nanorods (NRs) and carbon nanotubes (CNTs) (Figure 7g). (113) The latter is already proven for its neural recording and stimulation capabilities (114,115) because of their high surface roughness, highly porous nature, and large capacitance at the interface, and the former is the convenient choice for efficient and tunable light absorption. Moreover, the combination of two such systems led to improved charge separation and enhanced optoelectronic performance in comparison with previous studies. To motivate the use of NRs, wecompared three different nanocrystals (NCs), namely, CdSe QDs, CdSe/CdS core/shell QDs, and CdSe/CdS NRs (Figure 7h). As most of the colloidal QD synthesis ends up with nonpolar solvents such as hexane, toluene, and chloroform, it is critically important and a major challenge to render these NCs in an aqueous solution. Because of the advantage of ligand engineering of these NCs, the original ligands were replaced with the antioxidant tripeptide–glutathione (GSH), (113) which is also beneficial for the aqueous stability and biocompatibility, as it reduces the release of cadmium ions to the solution. CdSe, CdSe/CdS QDs, and CdSe/CdS NRs were all coated with GSH and conjugated with CNT films. CdSe GSH and CdSe/CdS GSH systems required higher loading concentrations than the CdSe/CdS NRs, approximately 9 × 1013, 1.75 × 1013, and 0.75 × 1013 particles cm–2, respectively. (113) In addition to the lower concentration, CdSe/CdS NRs generated much higher photocurrents (Figure 7h) because of their large surface area for efficient charge separation and high coupling with CNTs that was due to proper energy level alignment. Moreover, to evaluate the neural stimulation performance, they utilized light-insensitive embryonic chick retinas (E14). Retina or primary neurons are suitable application targets for neural interfaces working in the visible window because the eye itself is highly transparent in these wavelengths, suitable for wireless excitation mechanisms. The particular choice of the E14 stage is important because retinal cells are at the early maturation stage, and photoreceptors are not developed. (113,116) Excitation with 100 ms, 405 nm pulses revealed electrical response, and the intensity threshold of 3 mW cm–2 (Figure 7i) indicates the potential use of the biointerface under ambient light intensities. (113) The illumination intensity of the excitation and the exposure duration are particularly important for applications targeting the eye and brain. Light exposure above threshold intensities and exposure times may lead to thermal, thermoacoustic, and photochemical damage both in the targeted area as well as in the nearby tissues. (117,118) In comparison with previous studies, the combination of NR-CNT nanomaterial systems significantly reduces the threshold light intensity (Table 1) because effective charge generation and separation can be achieved via improved conjugation and proper band alignment. Therefore, this novel approach inspired various studies combining not only NRs with CNTs but also different semiconductor NCs with organic polymers and 2D/3D materials.
4.3. InP QD-Based Neural Interfaces
Previous efforts for designing effective neural interfaces had concentrated on cadmium (68) and mercury-based (67) QDs, following the chronological evolution of colloidal quantum dots. Alternatively, InP-based QDs are the improved candidates for neural interfaces in terms of lower cytotoxicity while having a high degree of tunable optical properties due to a large Bohr exciton radius (∼9 nm). (119) Moreover, European Union research on exposure of nanomaterials, NANOMICEX, provides the guidelines for future development of less-toxic, environmentally friendly nanoparticles for commercial and biomedical applications, for which InP-based ones hold a great promise. Although InP QDs in either core or core/shell structures were extensively studied in several different fields including solar cells, (120−123) fluorescent imaging markers, (120−123) bioconjugated sensors, (124) detectors, (125) luminescent solar concentrators, (126−129) and LEDs, (10,130,131) their potential in neural interfaces remained unrevealed. On the other hand, their biocompatibility for both in vitro and in vivo studies was carefully studied in the literature, (132) which they were used as optical probes for imaging and as nanocarriers for drug delivery applications. (133)
The InP core material is a standard nanostructure that can be used for light-to-charge conversion, whereas core/shell heterostructures with type II band alignment have attractive properties for optoelectronic applications owing to the ability to control the spatial confinement regimes of charge carriers throughout the core and shell materials. In this context, core/shell structures with less toxic materials have been favorably used for photostimulation applications. The first study incorporating type II QDs, namely, InP/ZnO core/shell QDs (in thin-film layered configuration), showed its high potential for neural interfaces by generating hyperpolarization of the cell membrane. (69) The crystalline ZnO shell builds the type II structure because of its wide bandgap (3.37 eV) (134) and similar conduction band level with InP, while protecting the core material from oxidative reactions, just like ZnS shelling of CdSe core QDs discussed above. For the shell growth, thermal decomposition of zinc acetylacetonate was utilized by heating the solution in reaction. (128) To promote the optoelectronic performance, we integrated InP/ZnO QDs onto a photoelectrode structure of glass:ITO/TiO2 to generate extracellular currents for photostimulation (Figure 8a left). The particular choice of TiO2 nanoparticles modified with 3-mercaptopropionic acid (3-MPA) facilitates the binding of InP/ZnO QDs on TiO2 thin film. Upon illumination, photogenerated electron–hole pairs dissociate to core and shell materials. The strong interparticle interaction between InP/ZnO-TiO2 materials is due to the proximity between these layers by the short-chain linker molecule (135) and this strategy couples the electron to an available state in TiO2. The coupled excited electron then diffuses toward the ITO layer, generating the photocurrent (Figure 8a right). The charge transfer between InP/ZnO QDs and TiO2 NPs led to a decreased average recombination lifetime of InP/ZnO QDs. (69) The optoelectronic measurements showed ∼3.4 nA photocurrent generation (Figure 8b) under a low light intensity of 4 μW cm–2 at 445 nm, which is 26-fold lower than the ocular safety limit (117) under pulsed illumination. Moreover, biocompatibility measurements with MTT for mitochondrial activity and LDH assay for membrane integrity of Neuro2A cells suggest high biocompatibility. The patch-clamp electrophysiology experiments on PC12 cells grown on the biointerface showed membrane hyperpolarization of −45 ± 10 mV under the same illumination intensity and evoked hyperpolarization-induced action potential, also called anode break excitation (Figure 8c), which is higher than the previous Cd (67) and He (68) QD-based studies at the same light intensity levels.
Figure 8
Figure 8. InP QD-based optoelectronic neural interfaces. (a) Schematic illustration of the photoelectrode fabrication steps and energy band diagram of the device architecture. (b) Photocurrent performance of TiO2, InP core and InP/ZnO QD coated biointerfaces. (c) Photostimulation of a PC12 cell on the photoelectrode under 4 μW mm–2 illumination (red bar, time period under illumination; blue bar, no illumination). Panels a, b and c reprinted with permission from ref (69). Copyright 2018 American Chemical Society. (d) Energy band diagram of bidirectional device architectures. (e) TEM image of the InP/ZnS QDs. (f) Transmembrane potential recordings of neurons on type I, type II, and ITO control samples (illumination: blue LED at 445 nm, 10 ms pulse width, 2 mW mm–2 optical power density; blue bar indicates the 10 ms “light on” interval). Panels d, e, and f reprinted with permission from ref (88). Copyright 2021 Frontiers.
To date, most of the QD-based biointerface designs for neural stimulation concentrated on the depolarization of the cell membrane as a merit of success, which is the first step for generating neural activation. In contrast, silencing the neural activity by hyperpolarization of neurons was also proven to be effective for certain neurological disorders such as epilepsy. (136) Moreover, achieving reliable and reversible inhibition of neurons enables systemic analysis of the cellular networks, which is highly motivated by neuroscientists. (137) Therefore, the development of neural interfaces that can control depolarization and hyperpolarization can bring a new perspective and add versatility to neural therapeutics. In this context, a recent study by Karatum et al. (88) utilized InP/ZnS core/shell QDs and metal oxide nanoparticles to design two different photovoltaic architectures, called type I (ITO/InP//ZnS QD/ZnO) and type II (ITO/TiO2/InP//ZnS QD) that can hyperpolarize and depolarize the neurons and lead to bidirectional control of the neural activity. Similar to recent studies, (34,132,138) ZnO and TiO2 NPs were chosen as hole blockers because their HOMO levels. The band alignment in these designs drifts photogenerated electrons toward the interfacial layer in type I device generating anodic photocurrents and toward the ITO layer in type II device generating cathodic photocurrents (Figure 8d). Therefore, InP/ZnS QDs were used for injecting anodic and cathodic currents to the biological medium, inducing either hyperpolarization or depolarization of the neural membrane, respectively (Figure 8e). Favorably, both types can elicit more than 25 mV photovoltage under low light intensities (10 mW cm–2). (88) For intensities as high as 57 mW cm–2, which is still lower than the threshold for thermal effects, type I and type II devices can produce −65 ± 7 mV and 175 ± 13 mV, respectively. Moreover, total charge injection in one charging/discharging phase was calculated as 1.29 μC cm–2 for type I and 4.12 μC cm–2 for type II biointerfaces. The generated photovoltage and charge injection levels are at similar levels with the required thresholds for neural stimulation. (40) Different from previous studies, photoactive layer thickness, which is a crucial aspect for designing photovoltaics and extensively studied by solar cell research, (139−141) was investigated in terms of depletion width and minority carrier diffusion length. (88) The sum of diffusion length and depletion width, which provides the required thickness for increasing charge extraction efficiency and harvesting of these charge carriers, is ∼165 nm and ∼185 nm for type I and type II devices, respectively. This analysis is particularly useful to determine the required layer thickness for the photoactive material and guide the researchers to design more efficient devices. Moreover, primary hippocampal neurons (PHNs) grown on the optimized devices were tested with MTT assay, indicating high cell viability. The electrophysiology experiments showed ∼50 mV hyperpolarization for type I biointerfaces and successful neural activation for different frequency stimuli (1, 2, 5, and 10 Hz) for type II devices with faradaic mechanisms under 2 mW mm–2, 445 nm illumination (Figure 8f). Therefore, this study showed the ability to control the direction of stimulation with systematic engineering of band alignment and nanostructures with potential device performance to activate or suppress the neural activity of primary cells. (142)
In addition to the regular photovoltaic device architecture, inspired from the dipole–dipole interaction so-called Förster energy transfer in biological systems, graded quantum dot systems, (i.e., also called as rainbow quantum dots), (143) can be utilized for building artificial antenna complexes just like photosynthetic systems (Figure 9a). (144) As motivated by the reduced toxicity of InP QDs, biocompatible quantum funnels were studied for directing light-induced charges to the device/cell interface. The study by Bahmani Jalali et al. (70) showed the synthesis and fabrication of multilayers of green-, yellow-, and red-emitting QDs in a graded structure to enable near-field dipole–dipole interaction (Figure 9b). QDs were engineered to achieve spectral overlap between the emission of the smaller QDs with the absorption spectrum of the larger QDs for efficient energy transfer toward the largest QD in the system. In the end of this excitonic transfer, the exciton dissociation is achieved via hole capturing by the S2– groups of the 3-MPA ligand and induced faradaic currents for membrane potential modulation. InP cores were coated with sufficiently thin ZnS shells for all green-, yellow-, and red-emitting QDs by a hot injection method that allow efficient dipole–dipole coupling between the energy gradient QDs. (145,146) The ZnS shell is important for both surface passivation of the defect states and to increase the quantum yield since higher QY offers an increase in Förster radius, (147) which enhances the nonradiative excitonic energy transfer efficiency. The passivation of the defect states also plays a significant role in photocurrent generation because it reduces the midgap state trapping of excited electrons. A careful fabrication strategy is required for this type of graded funnel structure because one donor QD can transfer its excited energy to three acceptor QDs located nearby the donor. (147) To facilitate this, we assembled three layers of red-emitting QDs on top of the green and yellow QD films with thicknesses of 14–24 nm (70) (Figure 9a). (148) The quantum funnel effect is proven by the optical characterizations showing weak photoluminescence in the green-yellow region followed by strong emission in the red spectral window, suggesting energy transfer from the donor QDs to red InP/ZnS acceptor QDs. Although the quantum funnel device showed lower absorption, its emission is stronger than the ungraded device, which was attributed to the trapped exciton recycling by energy transfer. (149) Likewise, this graded quantum funnel structure generated a higher photocurrent than the ungraded control structure under 450 nm 169 mW cm–2, 500 ms pulsed illumination. The graded quantum funnel device also performed better under low light intensity and shorter illumination pulses. Advantageously, MTT and LHD assays on SH-SY5Y cells indicated minimal effects on cell viability and membrane permeability. Therefore, the designed biointerface showed a high potential for neural stimulation. The single-cell patch-clamp electrophysiology experiments indicated the induced up to 1.5 mV membrane depolarization via 1s pulses and even generated ∼500 μV depolarization under the same light intensity with shorter 50 ms pulses (Figure 9c). The performance loss with shorter pulses is generally expected because the charging time required for depolarization is also shorter. One disadvantage of the system is the dependence on faradaic charge generation, which needs to be carefully controlled for potentially harmful effects on the cellular environment, and charge injection performance should be significantly increased. Nevertheless, this unconventional design using nanophotonics may bring a new perspective to the field for novel biointerface designs.
Figure 9
Figure 9. (a) Artificial antenna complexes made of rainbow InP quantum dots showing nonradiative energy transfer toward the cell interface. (b) (Upper inset) Photograph of the colloidal green-, yellow-, and red-emitting QDs under UV illumination. (Bottom) Energy band diagram of the quantum funnel biointerface (c) Photostimulation of the SH-SY5Y cell on the quantum funnel biointerface under illumination of 169 mW cm–2 with 50 ms illumination pulses. Panels a, b, and c reprinted with permission from ref (70). Copyright 2019 American Chemical Society. (d) Energy band alignment of the QD integrated biointerface. InP/ZnS core/shell and InP/ZnO/ZnS core/shell/shell QDs were incorporated into the photoelectrode architecture. (e) Photocurrent density traces of the devices with InP/ZnO/ZnS:PCBM volume ratios of 1:1 (black), 1:3 (red), and 1:7 (orange). The inset shows the components of the photocurrent. Capacitive current is the peak photocurrent reached after the light onset, whereas resistive current is the photocurrent remained after 90% of the illumination duration has passed. (f) Ratios of the capacitive to resistive components for devices with different QD:PCBM mixing ratios. Panels d, e, and f reprinted with permission from ref (83). Copyright 2021 Springer Nature.
In the aforementioned studies, the dominant physical phenomena for photocurrent generation was generally faradaic by nature. However, irreversible faradaic charge injection is not desired for long-term and safe cellular stimulation. To suppress the photoelectrochemical charge transfer and increase device efficiency, researchers proposed a QD–fullerene donor–acceptor nanoheterojunction. (83) In the study, a capacitive-dominant photoresponse was achieved using InP/ZnO/ZnS QDs and a fullerene derivative of [6,6]-phenyl C61 butyric acid methylester (PCBM) coated on glass:ITO/ZnO photoelectrode (Figure 10d). (83) In this architecture, the InP/ZnO/ZnS QDs were designed to delocalize the excited electrons to the ZnO shell and to confine holes in the InP core. Furthermore, subsequent ZnO and ZnS shells were grown on the InP core and increased the photoluminescence quantum yield from 7% (only core) to 28 and 70%, respectively, indicating the passivation of nonradiative surface defects. (150) The electronic properties of the proposed QD were investigated by quantum mechanical calculations (151) and compared with InP/ZnS QD. For InP/ZnS QD, the electron and hole are confine to the InP core but a fraction of the electron wave function penetrates to the ZnS shell, indicating smaller exciton binding energy for the shell in comparison with a single InP core QD. However, in InP/ZnO/ZnS QDs, the electron density is not fully confined in the ZnO shell but instead expands through the entire nanostructure, whereas the hole is fully confined in the InP core. This behavior can be attributed to the smaller effective mass, smaller spatial volume, and potential depth. (83) The decrease in the attractive Coulomb energy, i.e., the binding energy, due to spatially spread electron density and electron delocalization to the shell reveals the formation of the type II heterostructure, (69) which was also apparent in the electron–hole wave function overlap ratios of 0.89, 0.76, and 0.52 for the InP core, InP/ZnS, and InP/ZnO/ZnS QDs, respectively.
The InP/ZnO/ZnS QD was used as the donor and PCBM as the acceptor, and the blend showed rapid charging/discharging phases with quick rise/fall times of 200 μs. Moreover, the blending ratio, i.e., the number of acceptors per donor, plays a significant role in the photoresponse in terms of capacitive and faradaic processes. QD:PCBM volume with mixture ratios of 1:1, 1:3, and 1:7 resulted in capacitive/faradaic current ratios of 1.43, 2.5, and 1.47, respectively (Figure 9e, f). Therefore, the efficient charge separation, which is essential for capacitive charge generation, requires a sufficiently high and balanced number of acceptors per donor that is satisfied with a 1:3 blending ratio. The benchmark experiments for this blending ratio revealed photovoltage generation of 46 ± 4 mV under 445 nm, 57 mW cm–2 pulsed LED illumination. Comparatively, InP/ZnS based control device (glass:ITO, ZnO, InP/ZnS) showed slower charging/discharging phases with rise/fall times of 2 ms, indicating more resistive pathways for charge generation. The superior performance of InP/ZnO/ZnS-based biointerface over InP/ZnS based one can also be explained by the lower exciton binding energy of InP/ZnO/ZnS QD that increases the efficiency of the charge separation. (152) Thus, this study shows a novel perspective to combine novel heterostructures with fullerene materials to design nontoxic nanoheterojunctions for neural stimulation, which motivates further QD:fullerene combinations for efficient optoelectronic architectures.
4.4. PbS QD based neural interfaces
PbS QDs offer strong absorption from visible up to near-IR spectral range. (153) Moreover, in conjunction with polymers it can have enhanced nanomorphologies for effective charge dissociation. Because the band energy levels of PbS QDs have been conveniently used for bulk heterojunction (BHJ) solar cells, Srivastava et al. (71) utilized PbS QDs in a blend of the organic donor of P3HT and acceptor of PCBM for photostimulation of neurons. PbS QDs increased the overall absorbance by 14% and net absorbance by 3% at the pump wavelength of 450 nm in comparison with the control group without QDs. Moreover, the efficiency of the charge separation in the photoactive layer also depends on the phase separation between the domains in the BHJ of the P3HT:PCBM blend. The atomic force microscopy revealed smaller intermixed phase-separated domains for P3HT:PbS QDs:PCBM film with better homogeneity in comparison with the P3HT:PCBM film. (71) Likewise, the surface roughness of the PbS QDs (1.03 nm) integrated film is higher than the control (0.51 nm), respectively. (71) This increase in surface roughness may also increase the charge collection between the interfaced layers. The benchmark values for the design indicated higher photocurrent generation performance for the optimized photoactive layer thickness, making the photovoltaic device a good candidate for neural interfaces. Furthermore, using PbS QDs in blend form with P3HT and PCBM may reduce the toxic effects for the cellular environment in comparison with the use of PbS as a single interfacial layer or without blending. The investigation of the cell viability and cell growth of SH-SY5Y cells seeded on the fabricated photoelectrodes revealed nonsignificant differences in cell viability tracked by MTT and tracking assays. (71) This design also utilizes intermediate layers to properly separate electrons and holes, enabling the charge generation dominated by the capacitive processes (Figure 10a, b). Patch-clamp electrophysiology experiments on the SH-SY5Y model cell line indicated that the biointerface can generate peak depolarization of ∼5 mV under low light intensities (1 mW cm–2) (Figure 10b), which also eliminates thermal effects that may induce to the cells. Therefore, this study showed the potential and safe use of PbS QDs mixed with organic photoactive polymers, motivating the use of different QDs and their blend with photoactive polymers for designing neural interfaces with better absorption and charge injection. Moreover, toward low-cost, large-scale, and safer synthesis of PbS QDs, greener precursors (i.e., thioacetamide (TAA)) have been proposed as the sulfur precursor. (154) Together with the advances in colloidal synthesis of QDs, PbS QD-based biointerfaces may offer unique features with NIR light absorption.
Figure 10
Figure 10. PbS- and AlSb-based neural interfaces. (a) (Top) Photocapacitive current levels of ITO/ZnO/P3HT:PCBM and ITO/ZnO/P3HT:PbS-QDs:PCBM photoelectrodes. (Bottom) Capacitive and faradaic components of type I, type II, and type III photoelectrodes under illumination of 10 ms light pulses with an intensity of 1 mW cm–2. The architecture for different types of biointerfaces was explained in panels c and d in Figure 6. (b) Membrane potential variation of SH-SY5Y cells grown on the type III biointerface in panel d upon light illumination (10 ms, 1 mW cm–2). Panels a and b reprinted with permission from ref (71). Copyright 2019 American Physical Society. (c) Atomic force microscopy (5 μm × 5 μm) of P3HT:PCBM surfaces with the optimized binary ratio of 2:1 on ITO/ZnO-coated glass substrates (left, 2D views; right, 3D views) with various thin film thicknesses (t) in tapping-mode. Ra shows the average surface roughness. (d) Peak photocurrent for the binary photoelectrodes as a function of various thin film thicknesses. Panels c and d reprinted with permission from ref (101). Copyright 2020 The Optical Society. (e) Structure of the AlSb integrated biointerface (left inset: cross-sectional SEM image) and energy band diagram of the proposed device. (f) Intracellular membrane potential change with respect to a distant Ag/AgCl electrode was measured after the photostimulation of primary hippocampal neurons on the glass:ITO control (red) and the biointerface (black) under illumination of 100 mW cm–2 with 20 ms illumination pulses. Blue semitransparent area shows the 445 nm light illumination period (g) Successful spike ratio of neurons on the glass:ITO/ZnO/P3HT control (gray) and the biointerface (black) under different illumination frequencies of 20 ms, 50 mW cm–2, and 20 pulses (n = 20, mean ± s.d.). Panels e, f and g reprinted with permission from ref (102). Copyright 2021 Springer Nature.
For further optimizations, the biointerface architecture glass:ITO/ZnO/P3HT:PbS QDs:PCBM was investigated. The study unrevealed that the weight percent of the PCBM blended with P3HT becomes a significant factor for optoelectronic performance by altering the device absorption. The adaptation of PbS QDs was further optimized in terms of device responsivity in P3HT:PCBM blends. (101) For that, different photoactive blend thicknesses (Figure 10c, d) and PbS QD loading ratio were investigated, and the optimum device thickness and loading ratio of 155 nm and 10 vol % were determined, respectively. (101) The atomic force microscopy revealed smaller intermixed phase-separated domains for a 155 nm thick P3HT:PCBM film with better homogeneity in comparison with the 210 nm thick P3HT:PCBM film (Figure 10c). Although reducing the blend thickness results in smoother surface morphology, increased inhomogeneity reduced the capacitive photocurrent. Therefore, there is an optimum surface roughness and surface homogeneity resulting in the best photocurrent injection performance (Figure 10d). The optimized device can induce 0.61 μC cm–2 under a 20 mW cm–2 intensity of green light with a high responsivity of 99 mA/W. This charge level is above the required threshold levels for neural stimulation of retinal tissue, (155) and advantageously, the charge generation process was dominantly capacitive. Moreover, the device was responsive to all visible spectrum, also suggesting the potential use for stimulating the retinal tissue. Electrophysiology experiments in vitro on PHNs extracted from E15-E17 Wistar Albino rats showed that the biointerface may elicit action potentials under 20 mW cm–2 illumination with very high duty-cycle pulsed stimulation called burst waveforms. The use of burst waveforms for stimulation enables the biointerface to work under ocular safety limits and fast charge accumulation in the cellular environment causing action potentials. Thus, this study suggests the optimization of nanomorphology can build hybrid material systems combining QDs with organic photoactive polymers for neural stimulation. However, in vivo cytotoxicity of PbS-based neural interfaces should be carefully studied for further studies because of its heavy-metal content.
4.5. AlSb QD-Based Neural Interfaces
A new type of colloidal nanocrystals, aluminum antimonide (AlSb), was recently introduced in 2019 (156) and is a less studied member of the III–V semiconductors. Physical growth methods (157) have been already utilized for the synthesis of AlSb semiconductors, particularly for near-IR optoelectronics (158) and quantum cascade lasers. (159) However, the introduced tunable colloidal synthesis of AlSb QDs provides the opportunity for solution-processable fabrication. Although most of the available colloidal quantum dots cover the blue and green windows in terms of absorption, the relatively narrow AlSb absorption spectrum in the blue region with a decaying tail for wavelengths longer than 450 nm can enable blue-light-selective optoelectronic performance. Moreover, a direct bandgap with HOMO and LUMO energies of −4.6 and −2.9 eV, respectively, makes AlSb NCs a perfect candidate for being adopted as a hole transfer layer (HTL) to be used with photoactive polymers (Figure 10e). The energy levels are convenient for integration with organic photoactive polymers such as P3HT, PCBM, ITIC, and PTB7-Th. (138,160,161) Inspired by classical photovoltaic device design, Han et al. developed the ITO/ZnO/P3HT/AlSb QD biointerface (Figure 10e) for neural stimulation of PHNs. (102) The band alignment between the compounds enabled convenient dissociation of photogenerated excitons in a photoactive P3HT polymer, routing electrons to the ITO layer and holes toward the AlSb QD layer. This proper alignment and effective dissociation generated an induced electric field gradient to the surrounding environment upon illumination. To prove the contribution of AlSb QDs, we compared the photoresponses under 445 nm blue and 630 nm red LED illumination. As expected from the absorption profile of AlSb QDs, the biointerface showed a nonsignificant performance increase under red light but a 2.3-fold higher photocurrent generation under blue light. Photoelectrochemical characterization (138) of this biointerface showed sufficient charge levels of 0.19 μC cm–2 to stimulate neurons in vitro. Advantageously, photoinduced charge generation showed a highly capacitive process with suppressed faradaic charge injection, only 0.92% of the total charge injection. On the other hand, the photochemical stability of QD-based neural interfaces in an aqueous environment has either never been studied or has not been fully evaluated in previous studies. The passive accelerated aging test with an acceleration factor of 32, conducted for 810 h, showed more than 36 months of operational lifetime in this study. (102) Biocompatibility tests in vitro showed no apoptosis or significant difference in cell viability for extracted PHNs. (102,162) The electrophysiology experiments on PHNs grown on the biointerface revealed efficient neural stimulation (Figure 10f, g) under 445 nm LED illumination up to 20 Hz (Figure 10g) with low jitter and latency. Advantageously, neural stimulation via the toxic-heavy-metal-free QDs is based on capacitive processes under low light intensities as low as 10 mW cm–2 under ocular safety limits. (102,117) Therefore, it is beneficial to combine different QD systems with photovoltaic devices either as the photoactive material or the interfacial layer as the ETL/HTL. There is still room for enhancement in device efficiency and responsivity, and getting inspiration from the methodologies in solar cell research to increase the device performance could result in superior architectures for high-frequency neural stimulation in different optical excitation windows.
4.6. Biocompatibility of QDs and Safety of the Stimulation
Another key challenge for implantable neural interfaces is to design and fabricate biocompatible devices while maintaining prolonged functional lifetime and efficiency in vivo. The main drawbacks for QD-based devices are (i) ion release from QDs, which might be potentially toxic or change the extracellular pH and reduce device performance, and (ii) the cellular intake by endocytic pathways. (163) A comprehensive study by Derfus et al. (164) investigated the cytotoxicity of CdSe QDs and proved that Cd-based QDs can induce toxicity under specific conditions. Particularly, surface oxidation may form Se–O2 molecules with desorption of Cd ions (Figure 11a), which inherently induce heavy metal toxicity. As investigated by other studies, (165) surface coating of QDs with either shells or various inert ligands slows down the surface oxidation processes, improving the biocompatibility (Figure 11b). Various surface coatings were previously used in the literature such as polyacrylate, (110) bovine serum albumin (BSA), (166) and ZnS, and they were proved to decrease the surface oxidation process. (164) Moreover, the role of UV-light excitation on increased cytotoxicity can be attributed to the enhanced oxidative effect of UV-light and elevated levels of free cadmium release from the QDs (Figure 11c). (164) Although ZnS and BSA surface coatings significantly reduce the cytotoxicity, it is not fully suppressed (Figure 11d). Different QD-based neural interface systems such as InP, PbS, and AlSb QDs were utilized. Particularly, InP QD-based systems showed superior cell viability (167) due to nontoxic material compounds in the final system (Figure 11e). Moreover, the effect of QDs on cellular processes were evaluated by investigating different biological aspects such as cell metabolic activity (using a 3-(4,5-dimethylth-iazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay) (Figure 8f), cellular cytotoxicity (using a lactate dehydrogenase (LDH) assay to evaluate plasma membrane damage) (Figure 11f), and membrane viability (using immunofluorescent materials such as 4′,6-diamidino-2-phenylindole (DAPI), a marker for membrane viability) (Figure 11g). The readers can refer to the references for more detailed QD cytotoxicity assessments. (20,166,168) Therefore, it is essential to evaluate the cytotoxicity of QDs for the targeted cells, tissues, and organs, both in vitro and in vivo, as well as under different concentrations, doses, and environmental conditions with properly engineered ligands and shells.
Figure 11
Figure 11. Biocompatibility of quantum dots for biomedical applications. (a) Oxidation mechanism of Cd-based nanoparticles. Reprinted with permission from ref (164). Copyright 2004 American Chemical Society. (b) Polymer encapsulation strategy for colloidal quantum dots. (A) Native nonpolar ligands remain intact and (B) amphiphilic polymer encapsulate the QD for water solubility. (C) Chemically reactive and polar group for bioconjugation. Reprinted with permission from ref (165). Copyright 2011 Elsevier. (c) Cell viability of hepatocytes as assessed by mitochondrial activity of CdSe QD-treated cultures relative to untreated controls under exposure to air and UV treatment. Reprinted with permission from ref (164). Copyright 2004 American Chemical Society. (d) Effect of ZnS coating on CdSe quantum dots on cytotoxicity and oxidation. Reprinted with permission from ref (164). Copyright 2004 American Chemical Society. (e) Cell viability of MCF-7 cells incubated with different concentrations of InP/ZnS QDs and CdSe/ZnS QDs for 24 h. Reprinted with permission from ref (167). Copyright 2017, Royal Society of Chemistry. (f) Cell viability and cytotoxicity assessment of InP/ZnO quantum dots with MTT (upper left), LDH assay (upper right), and visualized cell morphology via DAPI staining and actin immunolabeling (bottom, scale bar: 50 μm). Reprinted with permission from ref (69). Copyright 2018 American Chemical Society. (g) Immunofluorescence imaging of primary hippocampal neurons grown on AlSb NC-coated biointerfaces. PHNs costained with DAPI, Anti-NeuN (red), and anti-F-actin (green) (scale bar: 75 μm). Reprinted with permission from ref (102). Copyright 2021 Springer Nature.
QD-based biointerfaces modulate neural activity by electrochemical currents resulting from conversion of optical energy to electrical energy. The damage mechanisms and charge injection thresholds for electrical stimulation have previously been investigated in detail. (85,169−171) The QD-based biointerfaces reported up to date have photogenerated charge densities on the order of few μC cm–2 and current densities of maximum few mA cm–2, which are typically below the damage thresholds for brain and retina. (169,172) On the other hand, attention must be paid while using the biointerfaces that generate charge-imbalanced monophasic stimulation pulses (88,113) to avoid possible electrode and tissue damage, although charge-balance does not necessarily indicate electrochemical balance (see Merrill et al. for more on this (85)). Therefore, capacitive biointerfaces are favorable and they typically provide charge-balanced biphasic waveforms.
5. Perspective & Conclusion
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Quantum-dot-based neural interfaces showed remarkable progress in terms of responsivity and transition toward nontoxic quantum dots. As a next step, seamless integration with targeted tissue via minimally invasive methods while simultaneously increasing spatiotemporal resolution and efficiency remains as an important challenge. For that purpose, the transition toward “single-nanocrystal-level” neural interfaces hold high promise. However, there are fundamental challenges that need to overcome at nanoscale. One of the challenges is the realization of nanocrystals made of metal, oxide, and semiconductor heterojunctions with large lattice mismatch for the control of the photogenerated charges. For example, the metal–semiconductor heterojunctions generally have high lattice mismatch and thus the semiconductors cannot be grown at high crystal quality. As a solution, nonepitaxial growth technique allows the deposition of a crystalline overlayer on a crystalline substrate with high lattice mismatch. (173,174) For the heterojunctions with low lattice mismatch, epitaxial growth techniques such as a successive ionic layer adsorption and reaction (SILAR) can be applied. Hence, the movement of the photogenerated charge carriers can be well controlled for the targeted charge-transfer mechanism at the electrode–electrolyte interface. Moreover, anisotropic growth of the crystal may lead to spatially separate stimulation and return nanoelectrodes for efficient modulation of neural activity.
After nanocrystals are properly designed and synthesized, they can be conjugated with functional groups (secondary antibodies) and specifically bind to external motifs of neuronal membrane proteins (antigens) via primary antibodies. Once bound to a neuron, these nanocrystals can transduce pulses of light into capacitive or pseudocapacitive currents to modulate the transmembrane potential. The photocurrent can be generated via photogenerated potential change between the nanocrystal and cellular environment that can stimulate or inhibit the neuronal activity at single-cell level. Thus, the combination of single-nanocrystal-level neural interfaces with targeted delivery to the nervous system can be beneficial to treat a wide variety of nervous system diseases at an unprecedented degree. However, state of the art QD-based systems require short-wavelength excitation, which limit their effective use in in vivo therapeutic applications because of the short penetration length of visible light into targeted tissues. Upconversion nanoparticles (UCNPs) and their hybrid systems with QDs enable the use of low-energy NIR light for photostimulation of neurons to overcome this challenge. UCNPs absorb low energy photons, convert them to high-energy visible photons, and excite QDs. (175) UCNPs have attracted tremendous interest in optogenetics, bioimaging, and light-activated drug release. (175) Numerous studies in these areas enabled efficient and biocompatible UCNP systems. Particularly, their efficient use in neural modulation has been investigated as the visible photon sources required by optogenetics. (176−180) Moreover, plasmonic nanostructures have been utilized to enhance upconversion efficiency (181,182) and their stand-alone use was also studied for modulation of neural activity. (183,184) Therefore, hybrid systems of UCNPs, photoactive polymers, and plasmonic nanostructures with QDs can offer numerous advantages and opportunities for wireless in vivo studies and clinical research.
Although QDs in free-standing conditions have not yet achieved modulation of neural activity, it has been shown that free-standing silicon nanowires can reproducibly evoke action potentials in primary neurons via the photoelectrochemical pathway. (142) The ability to build p-type/intrinsic/n-type (PIN) silicon nanowires and to control the doping profiles in a sensitive way render these nanostructures versatile candidates for opto-bioelectronic applications. (185,186) Moreover, they can also be integrated in composite mesh structures for building flexible and conformable biointerfaces. (185) Up to now, these systems have operated with high optical power densities using lasers compared to the QD-based systems, which were mostly excited with the light-emitting diodes operating under lower irradiance levels. On the other hand, the ability to modulate neural activity via a single free-standing nanowire motivates the use of single-QD systems for achieving spatially selective stimulation instead of using planar solid films of QDs. With these future improvements, quantum opto-bioelectronics can advance optical control of the nervous system, broaden operational spectral windows, and improve functionality.
On the other hand, more extensive and thorough evaluation of biocompatibility and acute/chronic immune response are needed, particularly for colloidal use of QDs. QD-based biointerfaces can be either injected like nanoparticle-based systems or implanted as building blocks of biointerfaces to the targeted tissue. (29,30) To date, various techniques such as surface coatings with biocompatible materials such as silica, which is used in various optical (187) and biomedical applications, (188) BSA, ZnS, and ZnO, which are dietary molecules, (164) have been used for reduced cytotoxicity. However, they may either reduce device efficiency or are not sufficient to fully eliminate long-term biological effects. Collaborative efforts of nanoengineering, material science, and bioelectronics can offer new material opportunities to simultaneously achieve efficiency and biocompatibility to address this challenge.
Though neural stimulation is mostly used for direct activation/inhibition of neural activity, there is an increasing and extensive research on its potential in neural differentiation and regeneration. (189) Although electrical stimulation is the most well-studied and established technique on this subject, recent studies (42,189,190) showed that optoelectronic stimulation via nanomaterials, (191−193) particularly nanoparticles, (29,194) can bring new advantages as an alternative to electrical stimulation with the progress in cellular-scale optoelectronics. (195) In addition, there are alternative stimulation methods such as magnetic, ultrasound, and a combination of the multimodal approaches that can lead to unconventional neurostimulation strategies.
Monitoring action potentials in neurons via electric-field-modulated QD photoluminescence is a recently developed technique for recording purposes. (22) Conventionally, the optical readout of neural activity is achieved by chemical Ca2+ indicators. However, the photoluminescence kinetics of commercial Ca2+ indicators are much slower than the neural activity time scale (e.g., 10–100 s for indicators vs. 1–100 ms for neural voltage signals). (22) Comparatively, QDs can operate at recombination lifetimes with a resolution of tens of nanoseconds range. The electric field within the vicinity of the cell membrane can couple to the QDs that can shift emission intensity, photoluminescence peak, and emission bandwidth. (196−200) Furthermore, Förster resonant energy transfer (FRET) between the QD–quencher pair (200) can be also used for imaging of neuronal action potentials, which can be measured and interpreted with conventional spectroscopic devices. In addition, near-unity QDs can be either used for efficient FRET-systems or integrated into photovoltaic device architecture where the nontransferred or dissociated remaining excitons can efficiently recombine and the luminescence signal may be used for sensing in different configurations. Because QDs with a higher quantum efficiency yielded higher photocurrents due to nontrapped charges, near-unity QDs can be an interesting candidate for simultaneous sensing and stimulation devices. (69,88) Moreover, such devices can be a powerful alternative to change metabolic activity and monitor drug-induced effects for pharmalogical profiling, in addition to the recent label-free techniques. (185,201−203)
In summary, we discussed the foundations and progress of colloidal quantum dot based neural interfaces for photostimulation of neurons. Despite recent advances, integration of colloidal quantum dots cannot completely reach the silicon- or polymer-based neural interfaces in terms of device efficiency yet. However, we expect that advances in chemical synthesis techniques and colloidal nanosystems combined with bioelectronics can lead to various alternative QD-based devices for neuroscience and treatment of dysfunctional neuronal circuits. For that, recent advances in the related fields have made a great scientific basis for next-generation noninvasive, ultrasmall, and effective neural interfaces. We hope that the recent efforts and challenges discussed in this review will provide insight for future research and motivation for next-generation scientists on these emerging nanomaterial systems and their use in neural interfaces.
Author Information
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Sedat Nizamoglu - Department of Electrical and Electronics Engineering, Koç University, Istanbul 34450, Turkey; Graduate School of Biomedical Science and Engineering, Koç University, Istanbul 34450, Turkey;
https://orcid.org/0000-0003-0394-5790;
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Mertcan Han - Department of Electrical and Electronics Engineering, Koç University, Istanbul 34450, Turkey;https://orcid.org/0000-0002-3543-5894
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Onuralp Karatum - Department of Electrical and Electronics Engineering, Koç University, Istanbul 34450, Turkey;https://orcid.org/0000-0002-7669-9589
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M.H. and O.K. contributed equally to this paper.
Acknowledgments
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This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement 639846). S.N. also acknowledges the support by the Turkish Academy of Sciences (TÜBA-GEBIP; The Young Scientist Award Program) and the Science Academy of Turkey (BAGEP; The Young Scientist Award Program).
References
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9Hanifi, D. A.; Bronstein, N. D.; Koscher, B. A.; Nett, Z.; Swabeck, J. K.; Takano, K.; Schwartzberg, A. M.; Maserati, L.; Vandewal, K.; van de Burgt, Y.; Salleo, A.; Alivisatos, A. P. Redefining Near-Unity Luminescence in Quantum Dots with Photothermal Threshold Quantum Yield. Science (80-.). 2019, 363 (6432), 1199– 1202, DOI: 10.1126/science.aat3803Google ScholarThere is no corresponding record for this reference.
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10Won, Y. H.; Cho, O.; Kim, T.; Chung, D. Y.; Kim, T.; Chung, H.; Jang, H.; Lee, J.; Kim, D.; Jang, E. Highly Efficient and Stable InP/ZnSe/ZnS Quantum Dot Light-Emitting Diodes. Nature 2019, 575 (7784), 634– 638, DOI: 10.1038/s41586-019-1771-5Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXit1OhsrvP&md5=30a54f042a52e47575f0c9db1f9532b2Highly efficient and stable InP/ZnSe/ZnS quantum dot light-emitting diodesWon, Yu-Ho; Cho, Oul; Kim, Taehyung; Chung, Dae-Young; Kim, Taehee; Chung, Heejae; Jang, Hyosook; Lee, Junho; Kim, Dongho; Jang, EunjooNature (London, United Kingdom) (2019), 575 (7784), 634-638CODEN: NATUAS; ISSN:0028-0836. (Nature Research)Quantum dot (QD) light-emitting diodes (LEDs) are ideal for large-panel displays because of their excellent efficiency, color purity, reliability and cost-effective fabrication. Intensive efforts have produced red-, green- and blue-emitting QD-LEDs with efficiencies of 20.5 per cent4, 21.0 per cent and 19.8 per cent, resp., but it is still desirable to improve the operating stability of the devices and to replace their toxic cadmium compn. with a more environmentally benign alternative. The performance of indium phosphide (InP)-based materials and devices has remained far behind those of their Cd-contg. counterparts. Here we present a synthetic method of prepg. a uniform InP core and a highly sym. core/shell QD with a quantum yield of approx. 100 per cent. In particular, we add hydrofluoric acid to etch out the oxidative InP core surface during the growth of the initial ZnSe shell and then we enable high-temp. ZnSe growth at 340 °C. The engineered shell thickness suppresses energy transfer and Auger recombination in order to maintain high luminescence efficiency, and the initial surface ligand is replaced with a shorter one for better charge injection. The optimized InP/ZnSe/ZnS QD-LEDs showed a theor. max. external quantum efficiency of 21.4 per cent, a max. brightness of 100,000 candelas per square metre and an extremely long lifetime of a million hours at 100 candelas per square metre, representing a performance comparable to that of state-of-the-art Cd-contg. QD-LEDs. These as-prepd. InP-based QD-LEDs could soon be usable in com. displays.
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11Shirasaki, Y.; Supran, G. J.; Bawendi, M. G.; Bulović, V. Emergence of Colloidal Quantum-Dot Light-Emitting Technologies. Nat. Photonics 2013, 7 (1), 13– 23, DOI: 10.1038/nphoton.2012.328Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhvV2ntLfI&md5=9ce4673b68f86faa7c83212c053193c4Emergence of colloidal quantum-dot light-emitting technologiesShirasaki, Yasuhiro; Supran, Geoffrey J.; Bawendi, Moungi G.; Bulovic, VladimirNature Photonics (2013), 7 (1), 13-23CODEN: NPAHBY; ISSN:1749-4885. (Nature Publishing Group)A review. Since their inception 18 years ago, elec. driven colloidal quantum-dot light-emitting devices (QD-LEDs) have increased in external quantum efficiency from less than 0.01% to around 18%. The high luminescence efficiency and uniquely size-tunable color of soln.-processable semiconducting colloidal QDs highlight the potential of QD-LEDs for use in energy-efficient, high-color-quality thin-film display and solid-state lighting applications. Indeed, last year saw the first demonstrations of elec. driven full-color QD-LED displays, which foreshadow QD technologies that will transcend the optically excited QD-enhanced lighting products already available today. We here discuss the key advantages of using QDs as luminophores in LEDs and outline the operating mechanisms of four types of QD-LED. State-of-the-art visible-wavelength LEDs and the promise of near-IR and heavy-metal-free devices are also highlighted. As QD-LED efficiencies approach those of mol. org. LEDs, we identify the key scientific and technol. challenges facing QD-LED commercialization and offer our outlook for on-going strategies to overcome these challenges.
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12Pal, B. N.; Robel, I.; Mohite, A.; Laocharoensuk, R.; Werder, D. J.; Klimov, V. I. High-Sensitivity p-n Junction Photodiodes Based on Pbs Nanocrystal Quantum Dots. Adv. Funct. Mater. 2012, 22 (8), 1741– 1748, DOI: 10.1002/adfm.201102532Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xit1eitbw%253D&md5=b7a7b323a452b111c3a9171122539ec0High-Sensitivity p-n Junction Photodiodes Based on PbS Nanocrystal Quantum DotsPal, Bhola N.; Robel, Istvan; Mohite, Aditya; Laocharoensuk, Rawiwan; Werder, Donald J.; Klimov, Victor I.Advanced Functional Materials (2012), 22 (8), 1741-1748CODEN: AFMDC6; ISSN:1616-301X. (Wiley-VCH Verlag GmbH & Co. KGaA)Chem. synthesized nanocrystal quantum dots (NQDs) are promising materials for applications in soln.-processable optoelectronic devices such as light emitting diodes, photodetectors, and solar cells. Here, the authors fabricate and study two types of p-n junction photodiodes in which the photoactive p-layer is made from PbS NQDs while the transparent n-layer is fabricated from wide bandgap oxides (ZnO or TiO2). By using a p-n junction architecture the authors are able to significantly reduce the dark current compared to earlier Schottky junction devices without reducing external quantum efficiency (EQE), which reaches values of up to ∼80%. The use of this device architecture also allows the authors to significantly reduce noise and obtain high detectivity (>1012 cm Hz1/2 W-1) extending to the near IR past 1 μm. The spectral shape of the photoresponse exhibits a significant dependence on applied bias, and specifically, the EQE sharply increases around 500-600 nm at reverse biases >1 V. The authors attribute this behavior to a turn-on of an addnl. contribution to the photocurrent due to electrons excited to the conduction band from the occupied mid-gap states.
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13Konstantatos, G.; Howard, I.; Fischer, A.; Hoogland, S.; Clifford, J.; Klem, E.; Levina, L.; Sargent, E. H. Ultrasensitive Solution-Cast Quantum Dot Photodetectors. Nature 2006, 442 (7099), 180– 183, DOI: 10.1038/nature04855Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XmvFahtb4%253D&md5=3170d6484c19a8db1e9858804a720953Ultrasensitive solution-cast quantum dot photodetectorsKonstantatos, Gerasimos; Howard, Ian; Fischer, Armin; Hoogland, Sjoerd; Clifford, Jason; Klem, Ethan; Levina, Larissa; Sargent, Edward H.Nature (London, United Kingdom) (2006), 442 (7099), 180-183CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Soln.-processed electronic and optoelectronic devices offer low cost, large device area, phys. flexibility and convenient materials integration compared to conventional epitaxially grown, lattice-matched, cryst. semiconductor devices. Although the electronic or optoelectronic performance of these soln.-processed devices is typically inferior to that of those fabricated by conventional routes, this can be tolerated for some applications in view of the other benefits. Here we report the fabrication of soln.-processed IR photodetectors that are superior in their normalized detectivity (D*, the figure of merit for detector sensitivity) to the best epitaxially grown devices operating at room temp. We produced the devices in a single soln.-processing step, overcoating a prefabricated planar electrode array with an unpatterned layer of PbS colloidal quantum dot nanocrystals. The devices showed large photoconductive gains with responsivities greater than 103 A W-1. The best devices exhibited a normalized detectivity D* of 1.8 × 1013 jones (1 jones = 1 cm Hz1/2 W-1) at 1.3 μm at room temp.: today's highest performance IR photodetectors are photovoltaic devices made from epitaxially grown InGaAs that exhibit peak D* in the 1012 jones range at room temp., whereas the previous record for D* from a photoconductive detector lies at 1011 jones. The tailored selection of absorption onset energy through the quantum size effect, combined with deliberate engineering of the sequence of nanoparticle fusing and surface trap functionalization, underlie the superior performance achieved in this readily fabricated family of devices.
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14Pattantyus-Abraham, A. G.; Kramer, I. J.; Barkhouse, A. R.; Wang, X.; Konstantatos, G.; Debnath, R.; Levina, L.; Raabe, I.; Nazeeruddin, M. K.; Grätzel, M.; Sargent, E. H. Depleted-Heterojunction Colloidal Quantum Dot Solar Cells. ACS Nano 2010, 4 (6), 3374– 3380, DOI: 10.1021/nn100335gGoogle Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmsVGjsL8%253D&md5=b320b0603492a00bd1c6bb6e88c52c30Depleted-Heterojunction Colloidal Quantum Dot Solar CellsPattantyus-Abraham, Andras G.; Kramer, Illan J.; Barkhouse, Aaron R.; Wang, Xihua; Konstantatos, Gerasimos; Debnath, Ratan; Levina, Larissa; Raabe, Ines; Nazeeruddin, Mohammad K.; Gratzel, Michael; Sargent, Edward H.ACS Nano (2010), 4 (6), 3374-3380CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Colloidal quantum dot photovoltaics combine low-cost soln. processability with quantum size-effect tunability to match absorption with the solar spectrum. Rapid recent advances in colloidal quantum dot photovoltaics have led to impressive 3.6% air-mass 1.5 solar power conversion efficiencies. Two distinct device architectures and operating mechanisms have been advanced. The first, the Schottky device, was optimized and explained in terms of a depletion region driving electron-hole pair sepn. on the semiconductor side of a junction between an opaque low-work-function metal and a p-type colloidal quantum dot film. The second, the excitonic device, employed a colloidal quantum dot layer atop a transparent conductive oxide and was explained in terms of diffusive exciton transport via energy transfer followed by exciton sepn. at the type-II heterointerface between the colloidal quantum dot film and the transparent conductive oxide. Here we fabricate colloidal quantum dot photovoltaic devices on transparent conductive oxides and show that our devices rely on the establishment of a depletion region for field-driven charge transport and sepn., and that they also exploit the large bandgap of the transparent conductive oxide to improve rectification and block undesired hole extn. The resultant depleted-heterojunction solar cells provide a 5.1% air-mass 1.5 power conversion efficiency. The devices employ IR-bandgap size-effect-tuned PbS colloidal quantum dots, enabling broadband harvesting of the solar spectrum. We report the highest open-circuit voltages obsd. in solid-state colloidal quantum dot solar cells to date, as well as fill factors approaching 60%, through the combination of efficient hole blocking (heterojunction) and very small minority carrier d. (depletion) in the large-bandgap moiety.
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15Conibeer, G. Third-Generation Photovoltaics. Mater. Today 2007, 10 (11), 42– 50, DOI: 10.1016/S1369-7021(07)70278-XGoogle Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlGgs7bK&md5=f2c7fb746d26e7b1027585ed76c26865Third-generation photovoltaicsConibeer, GavinMaterials Today (Oxford, United Kingdom) (2007), 10 (11), 42-50CODEN: MTOUAN; ISSN:1369-7021. (Elsevier Ltd.)Third-generation approaches to photovoltaics (PVs) aim to achieve high-efficiency devices but still use thin-film, 2nd-generation deposition methods. The concept is to do this with only a small increase in areal costs and hence reduce the cost per W peak (this metric is the most widely used in the PV industry). Also, in common with Si-based, 2nd-generation, thin-film technologies, these will use materials that are both nontoxic and not limited in abundance. Thus, these 3rd-generation technologies will be compatible with large-scale implementation of PVs. The approach differs from 1st-generation fabrication of high-quality, low-defect, single-crystal PV devices that have high efficiencies approaching the limiting efficiencies for single-bandgap devices but use energy- and time-intensive techniques.
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16Konstantatos, G.; Badioli, M.; Gaudreau, L.; Osmond, J.; Bernechea, M.; De Arquer, F. P. G.; Gatti, F.; Koppens, F. H. L. Hybrid Graphene Quantum Dot Phototransistors with Ultrahigh Gain. Nat. Nanotechnol. 2012, 7 (6), 363– 368, DOI: 10.1038/nnano.2012.60Google Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XmsFOqsrs%253D&md5=d13d35fc059cdd63c5c1189123af8582Hybrid graphene-quantum dot phototransistors with ultrahigh gainKonstantatos, Gerasimos; Badioli, Michela; Gaudreau, Louis; Osmond, Johann; Bernechea, Maria; de Arquer, F. Pelayo Garcia; Gatti, Fabio; Koppens, Frank H. L.Nature Nanotechnology (2012), 7 (6), 363-368CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)Graphene is an attractive material for optoelectronics and photodetection applications because it offers a broad spectral bandwidth and fast response times. Weak light absorption and the absence of a gain mechanism that can generate multiple charge carriers from 1 incident photon have limited the responsivity of graphene-based photodetectors to ∼10-2 A W-1. A gain of ∼108 electrons per photon and a responsivity of ∼107 A W-1 in a hybrid photodetector that consists of monolayer or bilayer graphene covered with a thin film of PbS colloidal quantum dots is demonstrated. Strong and tunable light absorption in the quantum-dot layer creates elec. charges that are transferred to the graphene, where they recirculate many times due to the high charge mobility of graphene and long trapped-charge lifetimes in the quantum-dot layer. The device, with a specific detectivity of 7 × 1013 Jones, benefits from gate-tunable sensitivity and speed, spectral selectivity from the short-wavelength IR to the visible, and compatibility with current circuit technols.
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17Bruchez, M.; Moronne, M.; Gin, P.; Weiss, S.; Alivisatos, A. P. Semiconductor Nanocrystals as Fluorescent Biological Labels. Science (80-.). 1998, 281 (5385), 2013– 2016, DOI: 10.1126/science.281.5385.2013Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtlKgurw%253D&md5=db36fdbbfbc2facf264c3f98c1c8efcbSemiconductor nanocrystals as fluorescent biological labelsBruchez, Marcel, Jr.; Moronne, Mario; Gin, Peter; Weiss, Shimon; Alivisatos, A. PaulScience (Washington, D. C.) (1998), 281 (5385), 2013-2016CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Semiconductor nanocrystals were prepd. for use as fluorescent probes in biol. staining and diagnostics. Compared with conventional fluorophores, the nanocrystals have a narrow, tunable, sym. emission spectrum and are photochem. stable. The advantages of the broad, continuous excitation spectrum were demonstrated in a dual-emission, single-excitation labeling expt. on mouse fibroblasts. These nanocrystal probes are thus complementary and in some cases may be superior to existing fluorophores.
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18Biju, V.; Itoh, T.; Ishikawa, M. Delivering Quantum Dots to Cells: Bioconjugated Quantum Dots for Targeted and Nonspecific Extracellular and Intracellular Imaging. Chem. Soc. Rev. 2010, 39 (8), 3031– 3056, DOI: 10.1039/b926512kGoogle Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXptFygs7c%253D&md5=44314b2f8c76d4da56b63ceb1dc3a60aDelivering quantum dots to cells: bioconjugated quantum dots for targeted and nonspecific extracellular and intracellular imagingBiju, Vasudevanpillai; Itoh, Tamitake; Ishikawa, MitsuruChemical Society Reviews (2010), 39 (8), 3031-3056CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. Bioconjugated nanomaterials offer endless opportunities to advance both nanobiotechnol. and biomedical technol. In this regard, semiconductor nanoparticles, also called quantum dots, are of particular interest for multimodal, multifunctional and multiplexed imaging of biomols., cells, tissues and animals. The unique optical properties, such as size-dependent tunable absorption and emission in the visible and NIR regions, narrow emission and broad absorption bands, high photoluminescence quantum yields, large one- and multi-photon absorption cross-sections, and exceptional photostability are the advantages of quantum dots. Multimodal imaging probes are developed by interfacing the unique optical properties of quantum dots with magnetic or radioactive materials. Besides, cryst. structure of quantum dots adds scope for high-contrast x-ray and TEM imaging. Yet another unique feature of a quantum dot is its spacious and flexible surface which is promising to integrate multiple ligands and antibodies and construct multi-functional probes for bioimaging. In this crit. review, the authors will summarize recent advancements in the prepn. of biocompatible quantum dots, bioconjugation of quantum dots, and applications of quantum dots and their bioconjugates for targeted and nonspecific imaging of extracellular and intracellular proteins, organelles and functions (181 refs.).
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19Tada, H.; Higuchi, H.; Wanatabe, T. M.; Ohuchi, N. In Vivo Real-Time Tracking of Single Quantum Dots Conjugated with Monoclonal Anti-HER2 Antibody in Tumors of Mice. Cancer Res. 2007, 67 (3), 1138– 1144, DOI: 10.1158/0008-5472.CAN-06-1185Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXht1ynsLg%253D&md5=e472812ca77edd3c0192d6e1f3cb7b15In vivo Real-time Tracking of Single Quantum Dots Conjugated with Monoclonal Anti-HER2 Antibody in Tumors of MiceTada, Hiroshi; Higuchi, Hideo; Wanatabe, Tomonobu M.; Ohuchi, NoriakiCancer Research (2007), 67 (3), 1138-1144CODEN: CNREA8; ISSN:0008-5472. (American Association for Cancer Research)Studies with tracking of single nanoparticles are providing new insights into the interactions and processes involved in the transport of drug carriers in living mice. Here, the authors report the tracking of a single particle quantum dot (Qdot) conjugated with tumor-targeting antibody in tumors of living mice using a dorsal skinfold chamber and a high-speed confocal microscope with a high-sensitivity camera. Qdot labeled with the monoclonal anti-HER2 antibody was injected into mice with HER2-overexpressing breast cancer to analyze the mol. processes of its mechanistic delivery to the tumor. Movement of single complexes of the Qdot-antibody could be clearly obsd. at 30 frames/s inside the tumor through a dorsal skinfold chamber. The authors successfully identified six processes of delivery: initially in the circulation within a blood vessel, during extravasation, in the extracellular region, binding to HER2 on the cell membrane, moving from the cell membrane to the perinuclear region, and in the perinuclear region. The six processes were quant. analyzed to understand the rate-limiting constraints on Qdot-antibody delivery. The movement of the complexes at each stage was "stop-and-go.". The image anal. of the delivery processes of single particles in vivo provides valuable information on antibody-conjugated therapeutic nanoparticles, which will be useful in increasing therapeutic efficacy.
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20Michalet, X.; Pinaud, F. F.; Bentolila, L. A.; Tsay, J. M.; Doose, S.; Li, J. J.; Sundaresan, G.; Wu, A. M.; Gambhir, S. S.; Weiss, S. Quantum Dots for Live Cells, in Vivo Imaging, and Diagnostics. Science (80-.). 2005, 307 (5709), 538– 544, DOI: 10.1126/science.1104274Google Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmslOhtw%253D%253D&md5=03a28864cfd8c3c4269cc9919d1eafb9Quantum Dots for Live Cells, in Vivo Imaging, and DiagnosticsMichalet, X.; Pinaud, F. F.; Bentolila, L. A.; Tsay, J. M.; Doose, S.; Li, J. J.; Sundaresan, G.; Wu, A. M.; Gambhir, S. S.; Weiss, S.Science (Washington, DC, United States) (2005), 307 (5709), 538-544CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)A review. Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biol. applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biol. Recent examples of their exptl. use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-IR emission during surgery. The new generations of qdots have far-reaching potential for the study of intracellular processes at the single-mol. level, high-resoln. cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
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21Gao, X.; Cui, Y.; Levenson, R. M.; Chung, L. W. K.; Nie, S. In Vivo Cancer Targeting and Imaging with Semiconductor Quantum Dots. Nat. Biotechnol. 2004, 22 (8), 969– 976, DOI: 10.1038/nbt994Google Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmtFWru74%253D&md5=0762e06fe115b89ff1fc23a8959c9cc1In vivo cancer targeting and imaging with semiconductor quantum dotsGao, Xiaohu; Cui, Yuanyuan; Levenson, Richard M.; Chung, Leland W. K.; Nie, ShumingNature Biotechnology (2004), 22 (8), 969-976CODEN: NABIF9; ISSN:1087-0156. (Nature Publishing Group)We describe the development of multifunctional nanoparticle probes based on semiconductor quantum dots (QDs) for cancer targeting and imaging in living animals. The structural design involves encapsulating luminescent QDs with an ABC triblock copolymer and linking this amphiphilic polymer to tumor-targeting ligands and drug-delivery functionalities. In vivo targeting studies of human prostate cancer growing in nude mice indicate that the QD probes accumulate at tumors both by the enhanced permeability and retention of tumor sites and by antibody binding to cancer-specific cell surface biomarkers. Using both s.c. injection of QD-tagged cancer cells and systemic injection of multifunctional QD probes, we have achieved sensitive and multicolor fluorescence imaging of cancer cells under in vivo conditions. We have also integrated a whole-body macro-illumination system with wavelength-resolved spectral imaging for efficient background removal and precise delineation of weak spectral signatures. These results raise new possibilities for ultrasensitive and multiplexed imaging of mol. targets in vivo.
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22Efros, A. L.; Delehanty, J. B.; Huston, A. L.; Medintz, I. L.; Barbic, M.; Harris, T. D. Evaluating the Potential of Using Quantum Dots for Monitoring Electrical Signals in Neurons. Nat. Nanotechnol. 2018, 13 (4), 278– 288, DOI: 10.1038/s41565-018-0107-1Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXnsVeitLk%253D&md5=49901bf15ccf92fa34e835c1ef1b2e9bEvaluating the potential of using quantum dots for monitoring electrical signals in neuronsEfros, Alexander L.; Delehanty, James B.; Huston, Alan L.; Medintz, Igor L.; Barbic, Mladen; Harris, Timothy D.Nature Nanotechnology (2018), 13 (4), 278-288CODEN: NNAABX; ISSN:1748-3387. (Nature Research)A review. Success in the projects aimed at providing an advanced understanding of the brain is directly predicated on making crit. advances in nanotechnol. This Perspective addresses the unique interface of neuroscience and nanomaterials by considering the foundational problem of sensing neuron membrane voltage and offers a potential soln. that may be facilitated by a prototypical nanomaterial. Despite substantial improvements, the visualization of instantaneous voltage changes within individual neurons, whether in cell culture or in vivo, at both the single-cell and network level at high speed remains complex and problematic. The unique properties of semiconductor quantum dots (QDs) have made them powerful fluorophores for bioimaging. What is not widely appreciated, however, is that QD photoluminescence is exquisitely sensitive to proximal elec. fields. This property should be suitable for sensing voltage changes that occur in the active neuronal membrane. Here, we examine the potential role of QDs in addressing the important challenge of real-time optical voltage imaging.
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23Wang, Y.; Hu, R.; Lin, G.; Roy, I.; Yong, K.-T. Functionalized Quantum Dots for Biosensing and Bioimaging and Concerns on Toxicity. ACS Appl. Mater. Interfaces 2013, 5 (8), 2786– 2799, DOI: 10.1021/am302030aGoogle Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXit1eit78%253D&md5=6c35e87b022e0d76a112a83b31caa384Functionalized Quantum Dots for Biosensing and Bioimaging and Concerns on ToxicityWang, Yucheng; Hu, Rui; Lin, Guimiao; Roy, Indrajit; Yong, Ken-TyeACS Applied Materials & Interfaces (2013), 5 (8), 2786-2799CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)A review. Considerable efforts have been devoted to the development of novel functionalized nanomaterials for bio-oriented applications. With unique optical properties and molar scale prodn., colloidal photoluminescent quantum dots (QDs) have been properly functionalized with controlled interfaces as new class of optical probes with extensive use in biomedical research. In this review, we present a brief summary on the current research interests of using fine engineered QDs as a nanoplatform for biomedical sensing and imaging applications. In addn., recent concerns on the potential toxic effects of QDs are described as a general guidance for the development on QD formulations in future studies.
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24Song, C.; Knöpfel, T. Optogenetics Enlightens Neuroscience Drug Discovery. Nat. Rev. Drug Discovery 2016, 15 (2), 97– 109, DOI: 10.1038/nrd.2015.15Google Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFalsr3L&md5=6be5793208fa21fc454812e3093e4401Optogenetics enlightens neuroscience drug discoverySong, Chenchen; Knopfel, ThomasNature Reviews Drug Discovery (2016), 15 (2), 97-109CODEN: NRDDAG; ISSN:1474-1776. (Nature Publishing Group)Optogenetics - the use of light and genetics to manipulate and monitor the activities of defined cell populations - has already had a transformative impact on basic neuroscience research. Now, the conceptual and methodol. advances assocd. with optogenetic approaches are providing fresh momentum to neuroscience drug discovery, particularly in areas that are stalled on the concept of 'fixing the brain chem.'. Optogenetics is beginning to translate and transit into drug discovery in several key domains, including target discovery, high-throughput screening and novel therapeutic approaches to disease states. Here, we discuss the exciting potential of optogenetic technologies to transform neuroscience drug discovery.
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25Hart, W. L.; Kameneva, T.; Wise, A. K.; Stoddart, P. R. Biological Considerations of Optical Interfaces for Neuromodulation. Adv. Opt. Mater. 2019, 7 (19), 1900385, DOI: 10.1002/adom.201900385Google Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtlKltbjM&md5=d87c65ca500e77610bc6bce882e5791dBiological Considerations of Optical Interfaces for NeuromodulationHart, William L.; Kameneva, Tatiana; Wise, Andrew K.; Stoddart, Paul R.Advanced Optical Materials (2019), 7 (19), 1900385CODEN: AOMDAX; ISSN:2195-1071. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. The success of devices such as cochlear implants and pacemakers has led to increasing interest in new applications of artificial neural interfaces, ranging from brain-computer interfaces to vagus nerve stimulators. Both the established and emerging applications of neural interfaces have highlighted the need for improvements in spatial selectivity and reduced invasiveness, which in turn has driven growing interest in optical interfaces. The delivery of light to-and collection of light from-neural tissue presents distinct challenges for optical devices. This review presents the status of optical interface technologies with a focus on biol. considerations, such as biocompatibility, thermal loading, and tissue response. Attention is also paid to factors affecting the portability of optical interfaces, and issues around reliability and manufg. that need to be considered for successful translation. Indeed, it is imperative that engineers work closely with physiologists, clinicians, and patients when developing devices for research and the clinic. Finally, emerging trends and the potential for new technologies to disrupt the field are discussed. While many engineering challenges remain to be overcome, the achievements to date suggest that optical neuromodulation techniques have significant potential to be deployed in future for a wide range of practical therapeutic applications.
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26Zimmerman, J. F.; Tian, B. Nongenetic Optical Methods for Measuring and Modulating Neuronal Response. ACS Nano 2018, 12 (5), 4086– 4095, DOI: 10.1021/acsnano.8b02758Google Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXovVamsLw%253D&md5=020982a009a2feab47a93f23f4b54bb8Nongenetic Optical Methods for Measuring and Modulating Neuronal ResponseZimmerman, John F.; Tian, BozhiACS Nano (2018), 12 (5), 4086-4095CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. The ability to probe and modulate elec. signals sensitively at cellular length scales is a key challenge in the field of electrophysiol. Elec. signals play integral roles in regulating cellular behavior and in controlling biol. function. From cardiac arrhythmias to neurodegenerative disorders, maladaptive phenotypes in electrophysiol. can result in serious and potentially deadly medical conditions. Understanding how to monitor and to control these behaviors precisely and noninvasively represents an important step in developing next-generation therapeutic devices. As the authors develop a deeper understanding of neural network formation, electrophysiol. has the potential to offer fundamental insights into the inner working of the brain. In this Perspective, the authors explore traditional methods for examg. neural function, discuss recent genetic advances in electrophysiol., and then focus on the latest innovations in optical sensing and stimulation of action potentials in neurons. The authors emphasize nongenetic optical methods, as these provide high spatiotemporal resoln. and can be achieved with minimal invasiveness.
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27Lin, Y.; Fang, Y.; Yue, J.; Tian, B. Soft-Hard Composites for Bioelectric Interfaces. Trends Chem. 2020, 2 (6), 519– 534, DOI: 10.1016/j.trechm.2020.03.005Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhslejsLvN&md5=39c7c7164ac25f1f636b3d3d7d2018faSoft-Hard Composites for Bioelectric InterfacesLin, Yiliang; Fang, Yin; Yue, Jiping; Tian, BozhiTrends in Chemistry (2020), 2 (6), 519-534CODEN: TCRHBQ; ISSN:2589-5974. (Cell Press)A review. Bioelec. devices can probe fundamental biol. dynamics and improve the lives of human beings. However, direct application of traditional rigid electronics onto soft tissues can cause signal transduction and biocompatibility issues. One common mitigation strategy is the use of soft-hard composites to form more biocompatible interfaces with target cells or tissues. Here, we identify several soft-hard composite designs in naturally occurring systems. We use these designs to categorize the existing bioelec. interfaces and to suggest future opportunities. We discuss the utility of soft-hard composites for a variety of interfaces, such as in vitro and in vivo electronic or optoelectronic sensing and genetic and nongenetic modulation. We end the review by proposing new soft-hard composites for future bioelec. studies.
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28Medagoda, D. I.; Ghezzi, D. Organic Semiconductors for Light-Mediated Neuromodulation. Commun. Mater. 2021, 2 (1), 111, DOI: 10.1038/s43246-021-00217-zGoogle Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XotVCrsrk%253D&md5=16c961713cef4c0811f7476be34c1412Organic semiconductors for light-mediated neuromodulationMedagoda, Danashi Imani; Ghezzi, DiegoCommunications Materials (2021), 2 (1), 111CODEN: CMOAGE; ISSN:2662-4443. (Nature Portfolio)A review. Org. semiconductors have generated substantial interest in neurotechnol. and emerged as a promising approach for wireless neuromodulation in fundamental and applied research. Here, we summarise the range of applications that have been proposed so far, including retinal stimulation, excitation and inhibition of cultured neurons and regulation of biol. processes in other non-excitable cells from animal and plant origins. We also discuss the key chem. and phys. phenomena at the basis of the interaction between materials and cells. Finally, we provide an overview of future perspectives, exciting research opportunities and the remaining challenges hampering the translation of this blooming technol. into the clinic and industry.
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29Maya-Vetencourt, J. F.; Manfredi, G.; Mete, M.; Colombo, E.; Bramini, M.; Di Marco, S.; Shmal, D.; Mantero, G.; Dipalo, M.; Rocchi, A.; DiFrancesco, M. L.; Papaleo, E. D.; Russo, A.; Barsotti, J.; Eleftheriou, C.; Di Maria, F.; Cossu, V.; Piazza, F.; Emionite, L.; Ticconi, F.; Marini, C.; Sambuceti, G.; Pertile, G.; Lanzani, G.; Benfenati, F. Subretinally Injected Semiconducting Polymer Nanoparticles Rescue Vision in a Rat Model of Retinal Dystrophy. Nat. Nanotechnol. 2020, 15 (8), 698– 708, DOI: 10.1038/s41565-020-0696-3Google Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXht1Ontr3J&md5=714b031184a9b41207eb2b65b3bb02bdSubretinally injected semiconducting polymer nanoparticles rescue vision in a rat model of retinal dystrophyMaya-Vetencourt, Jose Fernando; Manfredi, Giovanni; Mete, Maurizio; Colombo, Elisabetta; Bramini, Mattia; Di Marco, Stefano; Shmal, Dmytro; Mantero, Giulia; Dipalo, Michele; Rocchi, Anna; DiFrancesco, Mattia L.; Papaleo, Ermanno D.; Russo, Angela; Barsotti, Jonathan; Eleftheriou, Cyril; Di Maria, Francesca; Cossu, Vanessa; Piazza, Fabio; Emionite, Laura; Ticconi, Flavia; Marini, Cecilia; Sambuceti, Gianmario; Pertile, Grazia; Lanzani, Guglielmo; Benfenati, FabioNature Nanotechnology (2020), 15 (8), 698-708CODEN: NNAABX; ISSN:1748-3387. (Nature Research)Abstr.: Inherited retinal dystrophies and late-stage age-related macular degeneration, for which treatments remain limited, are among the most prevalent causes of legal blindness. Retinal prostheses have been developed to stimulate the inner retinal network; however, lack of sensitivity and resoln., and the need for wiring or external cameras, have limited their application. Here we show that conjugated polymer nanoparticles (P3HT NPs) mediate light-evoked stimulation of retinal neurons and persistently rescue visual functions when subretinally injected in a rat model of retinitis pigmentosa. P3HT NPs spread out over the entire subretinal space and promote light-dependent activation of spared inner retinal neurons, recovering subcortical, cortical and behavioral visual responses in the absence of trophic effects or retinal inflammation. By conferring sustained light sensitivity to degenerate retinas after a single injection, and with the potential for high spatial resoln., P3HT NPs provide a new avenue in retinal prosthetics with potential applications not only in retinitis pigmentosa, but also in age-related macular degeneration.
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30Lorach, H.; Goetz, G.; Smith, R.; Lei, X.; Mandel, Y.; Kamins, T.; Mathieson, K.; Huie, P.; Harris, J.; Sher, A.; Palanker, D. Photovoltaic Restoration of Sight with High Visual Acuity. Nat. Med. 2015, 21 (5), 476– 482, DOI: 10.1038/nm.3851Google Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXnvFWjsrw%253D&md5=f7d079a8350f252a55cccd97ae318766Photovoltaic restoration of sight with high visual acuityLorach, Henri; Goetz, Georges; Smith, Richard; Lei, Xin; Mandel, Yossi; Kamins, Theodore; Mathieson, Keith; Huie, Philip; Harris, James; Sher, Alexander; Palanker, DanielNature Medicine (New York, NY, United States) (2015), 21 (5), 476-482CODEN: NAMEFI; ISSN:1078-8956. (Nature Publishing Group)Patients with retinal degeneration lose sight due to the gradual demise of photoreceptors. Elec. stimulation of surviving retinal neurons provides an alternative route for the delivery of visual information. We demonstrate that subretinal implants with 70-μm-wide photovoltaic pixels provide highly localized stimulation of retinal neurons in rats. The elec. receptive fields recorded in retinal ganglion cells were similar in size to the natural visual receptive fields. Similarly to normal vision, the retinal response to prosthetic stimulation exhibited flicker fusion at high frequencies, adaptation to static images and nonlinear spatial summation. In rats with retinal degeneration, these photovoltaic arrays elicited retinal responses with a spatial resoln. of 64 ± 11 μm, corresponding to half of the normal visual acuity in healthy rats. The ease of implantation of these wireless and modular arrays, combined with their high resoln., opens the door to the functional restoration of sight in patients blinded by retinal degeneration.
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31Green, M. A. Self-Consistent Optical Parameters of Intrinsic Silicon at 300 K Including Temperature Coefficients. Sol. Energy Mater. Sol. Cells 2008, 92 (11), 1305– 1310, DOI: 10.1016/j.solmat.2008.06.009Google Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGksbbI&md5=767829b037109986978cb974d333b6ecSelf-consistent optical parameters of intrinsic silicon at 300 K including temperature coefficientsGreen, Martin A.Solar Energy Materials & Solar Cells (2008), 92 (11), 1305-1310CODEN: SEMCEQ; ISSN:0927-0248. (Elsevier B.V.)An updated tabulation is presented of the optical properties of intrinsic Si, of particular interest in solar cell calcns. Improved values of absorption coeff., refractive index and extinction coeff. at 300 K are tabulated over the 0.25-1.45 μm wavelength range at 0.01 μm intervals. The self-consistent tabulation was derived from Kramers-Kronig anal. of updated reflectance data deduced from the literature. The inclusion of normalized temp. coeffs. allows extrapolation over a wide temp. range, with accuracy similar to that of available exptl. data demonstrated over the -24° to 200° range.
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32Lacour, S. P.; Courtine, G.; Guck, J. Materials and Technologies for Soft Implantable Neuroprostheses. Nat. Rev. Mater. 2016, 1 (10), 16063, DOI: 10.1038/natrevmats.2016.63Google Scholar32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVertLY%253D&md5=79c855fcd3ff9d92be084ee51d31a830Materials and technologies for soft implantable neuroprosthesesLacour, Stephanie P.; Courtine, Gregoire; Guck, JochenNature Reviews Materials (2016), 1 (10), 16063CODEN: NRMADL; ISSN:2058-8437. (Nature Publishing Group)Implantable neuroprostheses are engineered systems designed to restore or substitute function for individuals with neurol. deficits or disabilities. These systems involve at least one uni- or bidirectional interface between a living neural tissue and a synthetic structure, through which information in the form of electrons, ions or photons flows. Despite a few notable exceptions, the clin. dissemination of implantable neuroprostheses remains limited, because many implants display inconsistent long-term stability and performance, and are ultimately rejected by the body. Intensive research is currently being conducted to untangle the complex interplay of failure mechanisms. In this Review, we emphasize the importance of minimizing the phys. and mech. mismatch between neural tissues and implantable interfaces. We explore possible materials solns. to design and manuf. neurointegrated prostheses, and outline their immense therapeutic potential.
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33Ma, Y.; Zhang, Y.; Cai, S.; Han, Z.; Liu, X.; Wang, F.; Cao, Y.; Wang, Z.; Li, H.; Chen, Y.; Feng, X. Flexible Hybrid Electronics for Digital Healthcare. Adv. Mater. 2020, 32 (15), 1902062, DOI: 10.1002/adma.201902062Google Scholar33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXht1Oqt77O&md5=908565cd01c5d117e1c0a0ba5da2a435Flexible Hybrid Electronics for Digital HealthcareMa, Yinji; Zhang, Yingchao; Cai, Shisheng; Han, Zhiyuan; Liu, Xin; Wang, Fengle; Cao, Yu; Wang, Zhouheng; Li, Hangfei; Chen, Yihao; Feng, XueAdvanced Materials (Weinheim, Germany) (2020), 32 (15), 1902062CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Recent advances in material innovation and structural design provide routes to flexible hybrid electronics that can combine the high-performance elec. properties of conventional wafer-based electronics with the ability to be stretched, bent, and twisted to arbitrary shapes, revolutionizing the transformation of traditional healthcare to digital healthcare. Here, material innovation and structural design for the prepn. of flexible hybrid electronics are reviewed, a brief chronol. of these advances is given, and biomedical applications in bioelec. monitoring and stimulation, optical monitoring and treatment, acoustic imitation and monitoring, bionic touch, and body-fluid testing are described. In conclusion, some remarks on the challenges for future research of flexible hybrid electronics are presented.
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34Han, M.; Yildiz, E.; Kaleli, H. N.; Karaz, S.; Eren, G. O.; Dogru-Yuksel, I. B.; Senses, E.; Şahin, A.; Nizamoglu, S. Tissue-Like Optoelectronic Neural Interface Enabled by PEDOT:PSS Hydrogel for Cardiac and Neural Stimulation. Adv. Healthc. Mater. 2022, 2102160, DOI: 10.1002/adhm.202102160Google Scholar34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XpvFKnsg%253D%253D&md5=8d238bcc3ec4736665a8d788e6283dc0Tissue-Like Optoelectronic Neural Interface Enabled by PEDOT:PSS Hydrogel for Cardiac and Neural StimulationHan, Mertcan; Yildiz, Erdost; Kaleli, Huemeyra Nur; Karaz, Selcan; Eren, Guncem Ozgun; Dogru-Yuksel, Itir Bakis; Senses, Erkan; Sahin, Afsun; Nizamoglu, SedatAdvanced Healthcare Materials (2022), 11 (8), 2102160CODEN: AHMDBJ; ISSN:2192-2640. (Wiley-VCH Verlag GmbH & Co. KGaA)Optoelectronic biointerfaces have made a significant impact on modern science and technol. from understanding the mechanisms of the neurotransmission to the recovery of the vision for blinds. They are based on the cell interfaces made of org. or inorg. materials such as silicon, graphene, oxides, quantum dots, and π-conjugated polymers, which are dry and stiff unlike a cell/tissue environment. On the other side, wet and soft hydrogels have recently been started to attract significant attention for bioelectronics because of its high-level tissue-matching biomechanics and biocompatibility. However, it is challenging to obtain optimal opto-bioelectronic devices by using hydrogels requiring device, heterojunction, and hydrogel engineering. Here, an optoelectronic biointerface integrated with a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS, hydrogel that simultaneously achieves efficient, flexible, stable, biocompatible, and safe photostimulation of cells is demonstrated. Besides their interfacial tissue-like biomechanics, ≈34 kPa, and high-level biocompatibility, hydrogel-integration facilitates increase in charge injection amts. sevenfolds with an improved responsivity of 156 mA W-1, stability under mech. bending , and functional lifetime over three years. Finally, these devices enable stimulation of individual hippocampal neurons and photocontrol of beating frequency of cardiac myocytes via safe charge-balanced capacitive currents. Therefore, hydrogel-enabled optoelectronic biointerfaces hold great promise for next-generation wireless neural and cardiac implants.
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35Walling, M. A.; Novak, J. A.; Shepard, J. R. E. Quantum Dots for Live Cell and in Vivo Imaging. Int. J. Mol. Sci. 2009, 10 (2), 441– 491, DOI: 10.3390/ijms10020441Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitFOgsrk%253D&md5=bc6902516551bd6b1f6b81f0586e6849Quantum dots for live cell and in vivo imagingWalling, Maureen A.; Novak, Jennifer A.; Shepard, Jason R. E.International Journal of Molecular Sciences (2009), 10 (2), 441-491CODEN: IJMCFK; ISSN:1422-0067. (Molecular Diversity Preservation International)A review. In the past few decades, technol. has made immeasurable strides to enable visualization, identification, and quantitation in biol. systems. Many of these technol. advancements are occurring on the nanometer scale, where multiple scientific disciplines are combining to create new materials with enhanced properties. The integration of inorg. synthetic methods with a size redn. to the nano-scale has lead to the creation of a new class of optical reporters, called quantum dots. These semiconductor quantum dot nanocrystals have emerged as an alternative to org. dyes and fluorescent proteins, and are brighter and more stable against photobleaching than std. fluorescent indicators. Quantum dots have tunable optical properties that have proved useful in a wide range of applications from multiplexed anal. such as DNA detection and cell sorting and tracking, to most recently demonstrating promise for in vivo imaging and diagnostics. This review provides an in-depth discussion of past, present, and future trends in quantum dot use with an emphasis on in vivo imaging and its related applications.
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36Jonsson, A.; Inal, S.; Uguz, L.; Williamson, A. J.; Kergoat, L.; Rivnay, J.; Khodagholy, D.; Berggren, M.; Bernard, C.; Malliaras, G. G.; Simon, D. T. Bioelectronic Neural Pixel: Chemical Stimulation and Electrical Sensing at the Same Site. Proc. Natl. Acad. Sci. U. S. A. 2016, 113 (34), 9440– 9445, DOI: 10.1073/pnas.1604231113Google Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtlSlsrnF&md5=f998b6dfeeb3fbdfb1a3f9874444535fBioelectronic neural pixel: Chemical stimulation and electrical sensing at the same siteJonsson, Amanda; Inal, Sahika; Uguz, llke; Williamson, Adam J.; Kergoat, Loig; Rivnay, Jonathan; Khodagholy, Dion; Berggren, Magnus; Bernard, Christophe; Malliaras, George G.; Simon, Daniel T.Proceedings of the National Academy of Sciences of the United States of America (2016), 113 (34), 9440-9445CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Local control of neuronal activity is central to many therapeutic strategies aiming to treat neurol. disorders. Arguably, the best soln. would make use of endogenous highly localized and specialized regulatory mechanisms of neuronal activity, and an ideal therapeutic technol. should sense activity and deliver endogenous mols. at the same site for the most efficient feedback regulation. Here, we address this challenge with an org. electronic multifunctional device that is capable of chem. stimulation and elec. sensing at the same site, at the single-cell scale. Conducting polymer electrodes recorded epileptiform discharges induced in mouse hippocampal prepn. The inhibitory neurotransmitter, γ-aminobutyric acid (GABA), was then actively delivered through the recording electrodes via org. electronic ion pump technol. GABA delivery stopped epileptiform activity, recorded simultaneously and colocally. This multifunctional "neural pixel" creates a range of opportunities, including implantable therapeutic devices with automated feedback, where locally recorded signals regulate local release of specific therapeutic agents.
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37Warden, M. R.; Cardin, J. A.; Deisseroth, K. Optical Neural Interfaces. Annual Review of Biomedical Engineering. 2014, 16, 103– 129, DOI: 10.1146/annurev-bioeng-071813-104733Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVKgt77L&md5=bb92bb550fcb7cf25637e376c09020b4Optical neural interfacesWarden, Melissa R.; Cardin, Jessica A.; Deisseroth, KarlAnnual Review of Biomedical Engineering (2014), 16 (), 103-129CODEN: ARBEF7; ISSN:1523-9829. (Annual Reviews)A review. Genetically encoded optical actuators and indicators have changed the landscape of neuroscience, enabling targetable control and readout of specific components of intact neural circuits in behaving animals. Here, we review the development of optical neural interfaces, focusing on hardware designed for optical control of neural activity, integrated optical control and elec. readout, and optical readout of population and single-cell neural activity in freely moving mammals.
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38Mickle, A. D.; Won, S. M.; Noh, K. N.; Yoon, J.; Meacham, K. W.; Xue, Y.; McIlvried, L. A.; Copits, B. A.; Samineni, V. K.; Crawford, K. E.; Kim, D. H.; Srivastava, P.; Kim, B. H.; Min, S.; Shiuan, Y.; Yun, Y.; Payne, M. A.; Zhang, J.; Jang, H.; Li, Y.; Lai, H. H.; Huang, Y.; Park, S. Il; Gereau, R. W.; Rogers, J. A. A Wireless Closed-Loop System for Optogenetic Peripheral Neuromodulation. Nature 2019, 565 (7739), 361– 365, DOI: 10.1038/s41586-018-0823-6Google Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXlslKms7c%253D&md5=6ee4b7dfcb8852230d785faff81ee1c0A wireless closed-loop system for optogenetic peripheral neuromodulationMickle, Aaron D.; Won, Sang Min; Noh, Kyung Nim; Yoon, Jangyeol; Meacham, Kathleen W.; Xue, Yeguang; McIlvried, Lisa A.; Copits, Bryan A.; Samineni, Vijay K.; Crawford, Kaitlyn E.; Kim, Do Hoon; Srivastava, Paulome; Kim, Bong Hoon; Min, Seunghwan; Shiuan, Young; Yun, Yeojeong; Payne, Maria A.; Zhang, Jianpeng; Jang, Hokyung; Li, Yuhang; Lai, H. Henry; Huang, Yonggang; Park, Sung-Il; Gereau, IV, Robert W.; Rogers, John A.Nature (London, United Kingdom) (2019), 565 (7739), 361-365CODEN: NATUAS; ISSN:0028-0836. (Nature Research)The fast-growing field of bioelectronic medicine aims to develop engineered systems that can relieve clin. conditions by stimulating the peripheral nervous system1-5. This type of technol. relies largely on elec. stimulation to provide neuromodulation of organ function or pain. One example is sacral nerve stimulation to treat overactive bladder, urinary incontinence and interstitial cystitis (also known as bladder pain syndrome)4,6,7. Conventional, continuous stimulation protocols, however, can cause discomfort and pain, particularly when treating symptoms that can be intermittent (for example, sudden urinary urgency)8. Direct phys. coupling of electrodes to the nerve can lead to injury and inflammation9-11. Furthermore, typical therapeutic stimulators target large nerve bundles that innervate multiple structures, resulting in a lack of organ specificity. Here we introduce a miniaturized bio-optoelectronic implant that avoids these limitations by using (1) an optical stimulation interface that exploits microscale inorg. light-emitting diodes to activate opsins; (2) a soft, high-precision biophys. sensor system that allows continuous measurements of organ function; and (3) a control module and data analytics approach that enables coordinated, closed-loop operation of the system to eliminate pathol. behaviors as they occur in real-time. In the example reported here, a soft strain gauge yields real-time information on bladder function in a rat model. Data algorithms identify pathol. behavior, and automated, closed-loop optogenetic neuromodulation of bladder sensory afferents normalizes bladder function. This all-optical scheme for neuromodulation offers chronic stability and the potential to stimulate specific cell types.
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39Wang, Y.; Zhu, H.; Yang, H.; Argall, A. D.; Luan, L.; Xie, C.; Guo, L. Nano Functional Neural Interfaces. Nano Res. 2018, 11 (10), 5065– 5106, DOI: 10.1007/s12274-018-2127-4Google ScholarThere is no corresponding record for this reference.
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40Cogan, S. F. Neural Stimulation and Recording Electrodes. Annu. Rev. Biomed. Eng. 2008, 10 (1), 275– 309, DOI: 10.1146/annurev.bioeng.10.061807.160518Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGru7nE&md5=dc68b9ca9363036a7ceb7ee7b1b397f2Neural stimulation and recording electrodesCogan, Stuart F.Annual Review of Biomedical Engineering (2008), 10 (), 275-309CODEN: ARBEF7; ISSN:1523-9829. (Annual Reviews Inc.)A review. Elec. stimulation of nerve tissue and recording of neural elec. activity are the basis of emerging prostheses and treatments for spinal cord injury, stroke, sensory deficits, and neurol. disorders. An understanding of the electrochem. mechanisms underlying the behavior of neural stimulation and recording electrodes is important for the development of chronically implanted devices, particularly those employing large nos. of microelectrodes. For stimulation, materials that support charge injection by capacitive and faradaic mechanisms are available. These include titanium nitride, platinum, and iridium oxide, each with certain advantages and limitations. The use of charge-balanced waveforms and max. electrochem. potential excursions as criteria for reversible charge injection with these electrode materials are described and critiqued. Techniques for characterizing electrochem. properties relevant to stimulation and recording are described with examples of differences in the in vitro and in vivo response of electrodes.
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41Perlmutter, J. S.; Mink, J. W. Deep Brain Stimulation. Annu. Rev. Neurosci. 2006, 29 (1), 229– 257, DOI: 10.1146/annurev.neuro.29.051605.112824Google Scholar41https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XosVeitrw%253D&md5=5e2766e5160a19ab197e952e26befabeDeep brain stimulationPerlmutter, Joel S.; Mink, Jonathan W.Annual Review of Neuroscience (2006), 29 (), 229-257CODEN: ARNSD5; ISSN:0147-006X. (Annual Reviews Inc.)A review. Deep brain stimulation (DBS) has provided remarkable benefits for people with a variety of neurol. conditions. Stimulation of the ventral intermediate nucleus of the thalamus can dramatically relieve tremor assocd. with essential tremor or Parkinson disease (PD). Similarly, stimulation of the subthalamic nucleus or the internal segment of the globus pallidus can substantially reduce bradykinesia, rigidity, tremor, and gait difficulties in people with PD. Multiple groups are attempting to extend this mode of treatment to other conditions. Yet, the precise mechanism of action of DBS remains uncertain. Such studies have importance that extends beyond clin. therapeutics. Investigations of the mechanisms of action of DBS have the potential to clarify fundamental issues such as the functional anatomy of selected brain circuits and the relationship between activity in those circuits and behavior. Although we review relevant clin. issues, we emphasize the importance of current and future investigations on these topics.
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42Won, S. M.; Song, E.; Zhao, J.; Li, J.; Rivnay, J.; Rogers, J. A. Recent Advances in Materials, Devices, and Systems for Neural Interfaces. Adv. Mater. 2018, 30 (30), 1800534, DOI: 10.1002/adma.201800534Google ScholarThere is no corresponding record for this reference.
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43Jiang, Y.; Tian, B. Inorganic Semiconductor Biointerfaces. Nat. Rev. Mater. 2018, 473– 490, DOI: 10.1038/s41578-018-0062-3Google Scholar43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3MjitFGqsw%253D%253D&md5=2fee7437035092ac17f845f8d3d5b15bInorganic semiconductor biointerfacesJiang Yuanwen; Tian BozhiNature reviews. Materials (2018), 3 (12), 473-490 ISSN:2058-8437.Biological systems respond to and communicate through biophysical cues, such as electrical, thermal, mechanical and topographical signals. However, precise tools for introducing localized physical stimuli and/or for sensing biological responses to biophysical signals with high spatiotemporal resolution are limited. Inorganic semiconductors display many relevant electrical and optical properties, and they can be fabricated into a broad spectrum of electronic and photonic devices. Inorganic semiconductor devices enable the formation of functional interfaces with biological material, ranging from proteins to whole organs. In this Review, we discuss fundamental semiconductor physics and operation principles, with a focus on their behaviour in physiological conditions, and highlight the advantages of inorganic semiconductors for the establishment of biointerfaces. We examine semiconductor device design and synthesis and discuss typical signal transduction mechanisms at bioelectronic and biophotonic interfaces for electronic and optoelectronic sensing, optoelectronic and photothermal stimulation and photoluminescent in vivo imaging of cells and tissues. Finally, we evaluate cytotoxicity and highlight possible new material components and biological targets of inorganic semiconductor devices.
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44Won, S. M.; Song, E.; Reeder, J. T.; Rogers, J. A. Emerging Modalities and Implantable Technologies for Neuromodulation. Cell 2020, 181 (1), 115– 135, DOI: 10.1016/j.cell.2020.02.054Google Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXlslKksb8%253D&md5=26b121c5c5345eca9e6d0439afc26c24Emerging Modalities and Implantable Technologies for NeuromodulationWon, Sang Min; Song, Enming; Reeder, Jonathan T.; Rogers, John A.Cell (Cambridge, MA, United States) (2020), 181 (1), 115-135CODEN: CELLB5; ISSN:0092-8674. (Cell Press)A review. Techniques for neuromodulation serve as effective routes to care of patients with many types of challenging conditions. Continued progress in this field of medicine will require (1) improvements in our understanding of the mechanisms of neural control over organ function and (2) advances in technologies for precisely modulating these functions in a programmable manner. This review presents recent research on devices that are relevant to both of these goals, with an emphasis on multimodal operation, miniaturized dimensions, biocompatible designs, advanced neural interface schemes, and battery-free, wireless capabilities. A future that involves recording and modulating neural activity with such systems, including those that exploit closed-loop strategies and/or bioresorbable designs, seems increasingly within reach.
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45Tian, B.; Xu, S.; Rogers, J. A; Cestellos-Blanco, S.; Yang, P.; Carvalho-de-Souza, J. L; Bezanilla, F.; Liu, J.; Bao, Z.; Hjort, M. Roadmap on Semiconductor - Cell Biointerfaces. Phys. Biol. 2018, 15 (3), 031002, DOI: 10.1088/1478-3975/aa9f34Google Scholar45https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXkvFeksL8%253D&md5=eab786d8a3417aaf859b2082f2e82b9aRoadmap on semiconductor-cell biointerfacesTian, Bozhi; Xu, Shuai; Rogers, John A.; Cestellos-Blanco, Stefano; Yang, Peidong; Carvalho-de-Souza, Joao L.; Bezanilla, Francisco; Liu, Jia; Bao, Zhenan; Hjort, Martin; Cao, Yuhong; Melosh, Nicholas; Lanzani, Guglielmo; Benfenati, Fabio; Galli, Giulia; Gygi, Francois; Kautz, Rylan; Gorodetsky, Alon A.; Kim, Samuel S.; Lu, Timothy K.; Anikeeva, Polina; Cifra, Michal; Krivosudsky, Ondrej; Havelka, Daniel; Jiang, YuanwenPhysical Biology (2018), 15 (3), 031002/1-031002/32CODEN: PBHIAT; ISSN:1478-3975. (IOP Publishing Ltd.)A review. This roadmap outlines the role semiconductor-based materials play in understanding the complex biophys. dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mech. devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biol. components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biol. world.
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46Ekimov, A.; Onushchenko, A. Quantum Size Effect in Three-Dimensional Microscopic Semiconductor Crystals. JETP Lett. 1981, 34 (6), 345– 349Google ScholarThere is no corresponding record for this reference.
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47Efros, A. L.; Efros, A. L. Interband Absorption of Light in a Semiconductor Sphere. Sov. Phys. Semicond. 1982, 16 (7), 772– 775Google ScholarThere is no corresponding record for this reference.
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48Brus, L. E. A Simple Model for the Ionization Potential, Electron Affinity, and Aqueous Redox Potentials of Small Semiconductor Crystallites. J. Chem. Phys. 1983, 79 (11), 5566– 5571, DOI: 10.1063/1.445676Google Scholar48https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXhsF2ktw%253D%253D&md5=b0786ee952dcd7d2e759eacc7f20807fA simple model for the ionization potential, electron affinity, and aqueous redox potentials of small semiconductor crystallitesBrus, L. E.Journal of Chemical Physics (1983), 79 (11), 5566-71CODEN: JCPSA6; ISSN:0021-9606.Large semiconductor crystals have intrinsic electronic properties dependent upon the bulk band structure. As the crystal becomes small, a new regime is entered in which the electronic properties (excited states, ionization potential, electron affinity) should be strongly dependent upon the crystallite size and shape. These effects reflect quantized motion of the electron and hole in a confined space. The author addresses the possibility of a shift in the photochem. redox potential of one carrier, as a function of crystallite size. As a semiquant. guide, one might expect a shift on the order of h2/8em*R2 due to the kinetic energy of localization in the small crystallite. The elementary quantum mechanics of a charge crystallite was modeled using (1) the effective-mass approxn., (2) an electrostatic potential for dielec. polarization, and (3) penetration of the carrier outside the crystallite in the cases of small effective mass. Shifts of several tenths of an eV appear possible in crystallites of diam. 50 A. The carrier charge d. resides near the srystallite surface if the effective mass is very small.
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49Brus, L. E. Electron-Electron and Electron-Hole Interactions in Small Semiconductor Crystallites: The Size Dependence of the Lowest Excited Electronic State. J. Chem. Phys. 1984, 80 (9), 4403– 4409, DOI: 10.1063/1.447218Google Scholar49https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXitF2ltL8%253D&md5=9c2f22ebeefa7839f8c38538c6a0bc0cElectron-electron and electron-hole interactions in small semiconductor crystallites: the size dependence of the lowest excited electronic stateBrus, L. E.Journal of Chemical Physics (1984), 80 (9), 4403-9CODEN: JCPSA6; ISSN:0021-9606.The authors model, in an elementary way, the excited electronic states of semiconductor crystallites sufficiently small (∼50 Å diam) that the electronic properties differ from those of bulk materials. In this limit the excited states and ionization processes assume a mol.-like character. However, diffraction of bonding electrons by the periodic lattice potential remains of paramount importance in the crystallite electronic structure. The Schroedinger equation is solved at the same level of approxn. as used in the anal. of bulk cryst. electron-hole states (Wannier excitons). Kinetic energy is treated by the effective-mass approxn., and the potential energy is due to high-frequency dielec. solvation by at. core electrons. An approx. formula is given for the lowest excited electronic state energy. This expression is dependent upon bulk electronic properties and contains no adjustable parameters. The optical f no. for absorption and emission is also considered. The same model is applied to the problem of 2 conduction-band electrons in a small crystallite, to understand how the redox potential of excess electrons depends upon crystallite size.
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50Rossetti, R.; Nakahara, S.; Brus, L. E. Quantum Size Effects in the Redox Potentials, Resonance Raman Spectra, and Electronic Spectra of CdS Crystallites in Aqueous Solution. J. Chem. Phys. 1983, 79 (2), 1086– 1088, DOI: 10.1063/1.445834Google Scholar50https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3sXks1Witr4%253D&md5=b0e2f6417a44636d2ef5cd149717f26dQuantum size effects in the redox potentials, resonance Raman spectra, and electronic spectra of cadmium sulfide crystallites in aqueous solutionRossetti, R.; Nakahara, S.; Brus, L. E.Journal of Chemical Physics (1983), 79 (2), 1086-8CODEN: JCPSA6; ISSN:0021-9606.Size effects are reported in the excited electronic properties of small, crystallite CdS particles. The leading small size correction terms applicable to the photochem. redox potentials and lowest exciton energy are theor. modeled. The expt. involves controlled formation of CdS crystallites in aq. soln.
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51Brus, L. Electronic Wave Functions in Semiconductor Clusters: Experiment and Theory. J. Phys. Chem. 1986, 90 (12), 2555– 2560, DOI: 10.1021/j100403a003Google Scholar51https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XktFagtr0%253D&md5=480cab9cd92fd4d95d8be577a9bf7e0aElectronic wave functions in semiconductor clusters: experiment and theoryBrus, LouisJournal of Physical Chemistry (1986), 90 (12), 2555-60CODEN: JPCHAX; ISSN:0022-3654.Recent exptl. and theor. work in the size-dependent development of bulk electronic properties in semiconductor crystallites of ∼15 to several hundred are critically reviewed and discussed. Semiconducting electronic properties are explained in chem. valence terminol. These crystallites can be termed "clusters" because they are too small to have bulblike electronic wave functions even though they exhibit bulklike crystal structure. The principal exptl. evidence comes from the recent discovery that liq.-phase pptn. reactions can be controlled to make and stabilize cryst. semiconductor clusters in this size range. The cluster electronic properties can be studied optically in dil. colloidal solns. The cluster internal crystal structure is directly revealed by transmission electron microscopy. The results indicate that the approach of cluster electronic wave functions to the bulk Bloch MOs is exceedingly slow as a function of cluster size. This result can be anal. predicted in terms of the intrinsic electron delocalization present in cryst. materials with strong, directional chem. bonding.
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52Bera, D.; Qian, L.; Tseng, T. K.; Holloway, P. H. Quantum Dots and Their Multimodal Applications: A Review. Materials (Basel). 2010, 3 (4), 2260– 2345, DOI: 10.3390/ma3042260Google ScholarThere is no corresponding record for this reference.
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53Guzelturk, B.; Martinez, P. L. H.; Zhang, Q.; Xiong, Q.; Sun, H.; Sun, X. W.; Govorov, A. O.; Demir, H. V. Excitonics of Semiconductor Quantum Dots and Wires for Lighting and Displays. Laser Photon. Rev. 2014, 8 (1), 73– 93, DOI: 10.1002/lpor.201300024Google ScholarThere is no corresponding record for this reference.
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54Kambhampati, P. Unraveling the Structure and Dynamics of Excitons in Semiconductor Quantum Dots. Acc. Chem. Res. 2011, 44 (1), 1– 13, DOI: 10.1021/ar1000428Google Scholar54https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht12jurzI&md5=989710b3984767405fd6ebfad30e0a9aUnraveling the Structure and Dynamics of Excitons in Semiconductor Quantum DotsKambhampati, PatanjaliAccounts of Chemical Research (2011), 44 (1), 1-13CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)A review. The quantum dot, one of the central materials in nanoscience, is a semiconductor crystal with a phys. size on the nanometer length scale. It is often called an artificial atom because researchers can create nanostructures which yield properties similar to those of real atoms. By virtue of having a size in between mols. and solids, the quantum dot offers a rich palette for exploring new science and developing novel technologies. Although the phys. structure of quantum dots is known, a clear understanding of the resultant electronic structure and dynamics has remained elusive. However, because the electronic structure and dynamics of the dot, the excitonics, confer its function in devices such as solar cells, lasers, LEDs, and nonclassical photon sources, a more complete understanding of these properties is crit. for device development. In this Account, the authors use colloidal CdSe dots as a test bed upon which to explore four select issues in excitonic processes in quantum dots. The authors have developed a state-resolved spectroscopic approach which has yielded precise measurements of the electronic structural dynamics of quantum dots and has made inroads toward creating a unified picture of many of the key dynamic processes in these materials. The authors focus on four main topics of longstanding interest and controversy: (i) hot exciton relaxation dynamics, (ii) multiexcitons, (iii) optical gain, and (iv) exciton-phonon coupling. Using this state-resolved approach, the authors reconcile long standing controversies related to phenomena such as exciton cooling and exciton-phonon coupling and make surprising new observations related to optical gain and multiexcitons.
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55Murray, C. B.; Norris, D. J.; Bawendi, M. G. Synthesis and Characterization of Nearly Monodisperse CdE (E = S, Se, Te) Semiconductor Nanocrystallites. J. Am. Chem. Soc. 1993, 115 (19), 8706– 8715, DOI: 10.1021/ja00072a025Google Scholar55https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlsV2ltL8%253D&md5=3ec5ea3e17f7d9a177fec0283ccdfb34Synthesis and characterization of nearly monodisperse CdE (E = sulfur, selenium, tellurium) semiconductor nanocrystallitesMurray, C. B.; Norris, D. J.; Bawendi, M. G.Journal of the American Chemical Society (1993), 115 (19), 8706-15CODEN: JACSAT; ISSN:0002-7863.A simple route to the prodn. of high-quality CdE (E = S, Se, Te) semiconductor nanocrystallites is presented. Crystallites from ∼12 Å to ∼115 Å in diam. with consistent crystal structure, surface derivatization, and a high degree of monodispersity are prepd. in a single reaction. The synthesis is based on the pyrolysis of organometallic reagents by injection into a hot coordinating solvent. This provides temporally discrete nucleation and permits controlled growth of macroscopic quantities of nanocrystallites. Size selective pptn. of crystallites from portions of the growth soln. isolates samples with narrow size distributions (<5% root-mean-square in diam.). High sample quality results in sharp absorption features and strong band-edge emission which is tunable with particle size and choice of material. TEM and x-ray powder diffraction in combination with computer simulations indicate bulk structural properties in crystallites as small as 20 Å in diam.
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56Peng, X.; Manna, L.; Yang, W.; Wickham, J.; Scher, E.; Kadavanich, A.; Alivisatos, A. P. Shape Control of CdSe Nanocrystals. Nature 2000, 404 (6773), 59– 61, DOI: 10.1038/35003535Google Scholar56https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXhvVylsrw%253D&md5=51f1ad169e1c6ed7517bf147cdd65b23Shape control of CdSe nanocrystalsPeng, Xiaogang; Manna, Uberato; Yang, Weidong; Wickham, Juanita; Scher, Erik; Kadavanich, Andreas; Allvisatos, A. P.Nature (London) (2000), 404 (6773), 59-61CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Control of the growth kinetics of the II-VI semiconductor Cd selenide can be used to vary the shapes of the resulting particles from a nearly spherical morphol. to a rod-like one, with aspect ratios as large as ten to one. To maintain control of the growth rates surfactants of hexylphosphonic acid in trioctylphosphine oxide were used. TEM and powder x-ray diffraction confirmed the rod morphol. of the CdSe quantum rods.
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57Peng, Z. A.; Peng, X. Formation of High-Quality CdTe, CdSe, and CdS Nanocrystals Using CdO as Precursor [6]. J. Am. Chem. Soc. 2001, 123 (1), 183– 184, DOI: 10.1021/ja003633mGoogle Scholar57https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXos1Ckt7s%253D&md5=18a2cef890482b305ca2c694e2b27506Formation of high-quality CdTe, CdSe, and CdS nanocrystals using CdO as precursorPeng, Z. Adam; Peng, XiaogangJournal of the American Chemical Society (2001), 123 (1), 183-184CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A reproducible one-pot synthesis for high-quality quantum rods and dots of CdTe, CdSe, and CdS was developed using CdO as Cd precursor. CdO and trioctylphosphine oxide (TOPO) were dissolved in hexylphosphonic acid (HPA) or tetradecylphosphonic acid (TDPA) at 300°, and a stock soln. of the chalcogen was added. The samples were characterized by XRD, TEM, and absorption spectroscopy. The resulting nanocrystals were almost monodisperse without any size sepn. The growth kinetics showed a pattern similar to that of the best CdSe nanocrystals grown from Cd(Me)2 (Peng, 1998).
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58Hines, M. A.; Guyot-Sionnest, P. Synthesis and Characterization of Strongly Luminescing ZnS-Capped CdSe Nanocrystals. J. Phys. Chem. 1996, 100 (2), 468– 471, DOI: 10.1021/jp9530562Google Scholar58https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXhtVSgs7vN&md5=51d599a01b5db6c9cc3031be9f52c133Synthesis and Characterization of Strongly Luminescing ZnS-Capped CdSe NanocrystalsHines, Margaret A.; Guyot-Sionnest, PhilippeJournal of Physical Chemistry (1996), 100 (2), 468-71CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)The synthesis is described of ZnS-capped CdSe semiconductor nanocrystals using organometallic reagents by a 2-step single-flask method. XPS, TEM and optical absorption are consistent with nanocrystals contg. a core of nearly monodisperse CdSe of 27-30 Å diam. with a ZnS capping 6 ± 3 Å thick. The ZnS capping with a higher bandgap than CdSe passivates the core crystallite removing the surface traps. The nanocrystals exhibit strong and stable band-edge luminescence with a 50% quantum yield at room temp.
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59Dabbousi, B. O.; Rodriguez-Viejo, J.; Mikulec, F. V.; Heine, J. R.; Mattoussi, H.; Ober, R.; Jensen, K. F.; Bawendi, M. G. (CdSe)ZnS Core-Shell Quantum Dots: Synthesis and Characterization of a Size Series of Highly Luminescent Nanocrystallites. J. Phys. Chem. B 1997, 101 (46), 9463– 9475, DOI: 10.1021/jp971091yGoogle Scholar59https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXmvVamtr0%253D&md5=53d4f2c8e1a9e480695a7e239cfd32c9(CdSe)ZnS Core-Shell Quantum Dots: Synthesis and Optical and Structural Characterization of a Size Series of Highly Luminescent MaterialsDabbousi, B. O.; Rodriguez-Viejo, J.; Mikulec, F. V.; Heine, J. R.; Mattoussi, H.; Ober, R.; Jensen, K. F.; Bawendi, M. G.Journal of Physical Chemistry B (1997), 101 (46), 9463-9475CODEN: JPCBFK; ISSN:1089-5647. (American Chemical Society)The synthesis is reported of highly luminescent (CdSe)ZnS composite quantum dots with CdSe cores of diam. 23-55 Å. The narrow luminescence (fwhm ≤ 40 nm) from these composite dots spans most of the visible spectrum from blue through red with quantum yields of 30-50% at room temp. These materials were characterized using a range of optical and structural techniques. Optical absorption and luminescence spectroscopies probe the effect of ZnS passivation on the electronic structure of the dots. A combination of wavelength dispersive x-ray spectroscopy, XPS, small and wide angle x-ray scattering, and TEM were used to analyze the composite dots and det. their chem. compn., av. size, size distribution, shape, and internal structure. Using a simple effective mass theory, the energy shift was modeled for the 1st excited state for (CdSe)ZnS and (CdSe)CdS dots with varying shell thickness. Finally, the authors characterize the growth of ZnS on CdSe cores and det. how the structure of the ZnS shell influences the photoluminescence properties.
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60Bansal, B.; Godefroo, S.; Hayne, M.; Medeiros-Ribeiro, G.; Moshchalkov, V. V. Extended Excitons and Compact Heliumlike Biexcitons in Type-II Quantum Dots. Phys. Rev. B - Condens. Matter Mater. Phys. 2009, 80 (20), 205317, DOI: 10.1103/PhysRevB.80.205317Google Scholar60https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFartrvF&md5=ebf281ec977fc9de47ddeaf3422bf805Extended excitons and compact heliumlike biexcitons in type-II quantum dotsBansal, Bhavtosh; Godefroo, S.; Hayne, M.; Medeiros-Ribeiro, G.; Moshchalkov, V. V.Physical Review B: Condensed Matter and Materials Physics (2009), 80 (20), 205317/1-205317/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The authors used magnetophotoluminescence measurements to establish that InP/GaAs quantum dots have a type-II (staggered) band alignment. The av. excitonic Bohr radius and the binding energy are 15 nm and 1.5 meV, resp. When compared to bulk InP, the excitonic binding is weaker due to the repulsive (type-II) potential at the heterointerface. The measurements are extended to over almost 6 orders of magnitude of laser excitation powers and to magnetic fields of up to 50 T the excitation power can be used to tune the av. hole occupancy of the quantum dots and hence the strength of the electron-hole binding. The diamagnetic shift coeff. drastically reduces as the quantum dot ensemble makes a gradual transition from a regime where the emission is from (hydrogenlike) two-particle excitonic states to a regime where emission from (heliumlike) four-particle biexcitonic states also becomes significant.
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61Kagan, C. R.; Lifshitz, E.; Sargent, E. H.; Talapin, D. V. Building Devices from Colloidal Quantum Dots. Science (80-.). 2016, 353 (6302), aac5523, DOI: 10.1126/science.aac5523Google ScholarThere is no corresponding record for this reference.
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62Bareket-Keren, L.; Hanein, Y. Novel Interfaces for Light Directed Neuronal Stimulation: Advances and Challenges. Int. J. Nanomedicine 2014, 9 (SUPPL. 1), 65– 83, DOI: 10.2147/IJN.S51193Google Scholar62https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2cfpslegsg%253D%253D&md5=921cca87512f1a37c6cba99f214ce58dNovel interfaces for light directed neuronal stimulation: advances and challengesBareket-Keren Lilach; Hanein YaelInternational journal of nanomedicine (2014), 9 Suppl 1 (), 65-83 ISSN:.Light activation of neurons is a growing field with applications ranging from basic investigation of neuronal systems to the development of new therapeutic methods such as artificial retina. Many recent studies currently explore novel methods for optical stimulation with temporal and spatial precision. Novel materials in particular provide an opportunity to enhance contemporary approaches. Here we review recent advances towards light directed interfaces for neuronal stimulation, focusing on state-of-the-art nanoengineered devices. In particular, we highlight challenges and prospects towards improved retinal prostheses.
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63Winter, J. O.; Liu, T. Y.; Korgel, B. A.; Schmidt, C. E. Recognition Molecule Directed Interfacing between Semiconductor Quantum Dots and Nerve Cells. Adv. Mater. 2001, 13 (22), 1673– 1677, DOI: 10.1002/1521-4095(200111)13:22<1673::AID-ADMA1673>3.0.CO;2-6Google Scholar63https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovVSiurw%253D&md5=b0093837e197bc36350f82bbae8d2390Recognition molecule directed interfacing between semiconductor quantum dots and nerve cellsWinter, Jessica O.; Liu, Timothy Y.; Korgel, Brian A.; Schmidt, Christine E.Advanced Materials (Weinheim, Germany) (2001), 13 (22), 1673-1677CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH)Two routes to interface living neurons with semiconductor quantum dots (qdots) were demonstrated. The first uses known antibody-antigen recognition, and the second, a new approach, uses peptide recognition groups. These methods target receptors on the neuron surface, localizing semiconductor-biomol. binding to the exterior of the cell. The semiconductor qdots were attached to living neurons using both antibody and peptide recognition mols. The reduced overall luminescence intensity from the peptide-coated qdots compared to the antibody labeled qdots results from primary, specific binding, and not from differing material properties of the qdots. The proposed approach represents one of the first attempts to both attach an object to the cell and establish elec. interactions, particularly at the nanometer scale. This approach meets two major challenges, such as the reproducible neuron/device interfacing which is difficult due to uncontrollable neuronal growth, and the relatively large sepn. between the cell and the device that leads to poor electronic coupling. The peptide recognition mols. provide nanometer-scale control over the targeting and sepn. distance between the qdot and the cell.
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64Goldman, E. R.; Balighian, E. D.; Mattoussi, H.; Kuno, M. K.; Mauro, J. M.; Tran, P. T.; Anderson, G. P. Avidin: A Natural Bridge for Quantum Dot-Antibody Conjugates. J. Am. Chem. Soc. 2002, 124 (22), 6378– 6382, DOI: 10.1021/ja0125570Google Scholar64https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjsFCmsLo%253D&md5=cea4f4124e094a8b70d4e4200d461ad1Avidin: A Natural Bridge for Quantum Dot-Antibody ConjugatesGoldman, Ellen R.; Balighian, Eric D.; Mattoussi, Hedi; Kuno, M. Kenneth; Mauro, J. Matthew; Tran, Phan T.; Anderson, George P.Journal of the American Chemical Society (2002), 124 (22), 6378-6382CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors describe the prepn. and characterization of bioinorg. conjugates in which luminescent semiconductor CdSe-ZnS core-shell nanocrystal quantum dots (QDs) were coupled to antibodies through the use of an avidin bridge adsorbed to the nanocrystal surface via electrostatic self-assembly. Avidin, a highly pos. charged protein, was found to adsorb tightly to QDs modified with dihydrolipoic acid, which gives their surface a homogeneous neg. charge. QD conjugation to biotinylated antibodies subsequently is readily achieved. Fluoroimmunoassays utilizing these antibody conjugated QDs were successful in the detection of protein toxins (staphylococcal enterotoxin B, cholera toxin). QD-antibody conjugates formed in such a facile manner permit their use as a common immuno reagent, and in the development of multianalyte detection.
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65Michalet, X.; Pinaud, F. F.; Bentolila, L. A.; Tsay, J. M.; Doose, S.; Li, J. J.; Sundaresan, G.; Wu, A. M.; Gambhir, S. S.; Weiss, S. Quantum Dots for Live Cells, in Vivo Imaging, and Diagnostics. Science 2005, 307 (5709), 538– 544, DOI: 10.1126/science.1104274Google Scholar65https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmslOhtw%253D%253D&md5=03a28864cfd8c3c4269cc9919d1eafb9Quantum Dots for Live Cells, in Vivo Imaging, and DiagnosticsMichalet, X.; Pinaud, F. F.; Bentolila, L. A.; Tsay, J. M.; Doose, S.; Li, J. J.; Sundaresan, G.; Wu, A. M.; Gambhir, S. S.; Weiss, S.Science (Washington, DC, United States) (2005), 307 (5709), 538-544CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)A review. Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biol. applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biol. Recent examples of their exptl. use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-IR emission during surgery. The new generations of qdots have far-reaching potential for the study of intracellular processes at the single-mol. level, high-resoln. cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
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66Choi, M. S.; Meshik, X.; Dutta, M.; Stroscio, M. A. Screening Effect on Electric Field Produced by Spontaneous Polarization in ZnO Quantum Dot in Electrolyte. 18th Int. Work. Comput. Electron. IWCE 2015 2015, 2, 49– 51, DOI: 10.1109/IWCE.2015.7301943Google ScholarThere is no corresponding record for this reference.
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67Pappas, T. C.; Wickramanyake, W. M. S.; Jan, E.; Motamedi, M.; Brodwick, M.; Kotov, N. A. Nanoscale Engineering of a Cellular Interface with Semiconductor Nanoparticle Films for Photoelectric Stimulation of Neurons. Nano Lett. 2007, 7 (2), 513– 519, DOI: 10.1021/nl062513vGoogle Scholar67https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtlGku7rM&md5=4a964495da0b44af8419943bdc664a0eNanoscale Engineering of a Cellular Interface with Semiconductor Nanoparticle Films for Photoelectric Stimulation of NeuronsPappas, Todd C.; Wickramanyake, W. M. Shan; Jan, Edward; Motamedi, Massoud; Brodwick, Malcolm; Kotov, Nicholas A.Nano Letters (2007), 7 (2), 513-519CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)The remarkable optical and elec. properties of nanostructured materials are considered now as a source for a variety of biomaterials, biosensing, and cell interface applications. In this study, the authors report the first example of hybrid bionanodevice where absorption of light by thin films of quantum confined semiconductor nanoparticles of HgTe produced by the layer-by-layer assembly stimulate adherent neural cells via a sequence of photochem. and charge-transfer reactions. The authors also demonstrate an example of nanoscale engineering of the material driven by biol. functionalities.
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68Lugo, K.; Miao, X.; Rieke, F.; Lin, L. Y. Remote Switching of Cellular Activity and Cell Signaling Using Light in Conjunction with Quantum Dots. Biomed. Opt. Express 2012, 3 (3), 447, DOI: 10.1364/BOE.3.000447Google Scholar68https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjslOls7o%253D&md5=4ea5116f559857e00fd31cb7ce6690d2Remote switching of cellular activity and cell signaling using light in conjunction with quantum dotsLugo, Katherine; Miao, Xiaoyu; Rieke, Fred; Lin, Lih Y.Biomedical Optics Express (2012), 3 (3), 447-454CODEN: BOEICL; ISSN:2156-7085. (Optical Society of America)Stimulating cells by using light is a non-invasive technique that provides flexibility in probing different locations while minimizing unintended effects on the system. We propose a new way to make cells photosensitive without using genetic or chem. manipulation, which alters natural cells, in conjunction with Quantum Dots (QDs). Remote switching of cellular activity by optical QD excitation is demonstrated by integrating QDs with cells: CdTe QD films with prostate cancer (LnCap) cells, and CdSe QD films and probes with cortical neurons. Changes in membrane potential and ionic currents are recorded by using the patch-clamp method. Upon excitation, the ion channels in the cell membrane were activated, resulting in hyperpolarization or depolarization of the cell.
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69Bahmani Jalali, H.; Mohammadi Aria, M.; Dikbas, U. M.; Sadeghi, S.; Ganesh Kumar, B.; Sahin, M.; Kavakli, I. H.; Ow-Yang, C. W.; Nizamoglu, S. Effective Neural Photostimulation Using Indium-Based Type-II Quantum Dots. ACS Nano 2018, 12 (8), 8104– 8114, DOI: 10.1021/acsnano.8b02976Google Scholar69https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtlCnsbrL&md5=9b9b80aa422905c9d52332f020094b69Effective Neural Photostimulation Using Indium-Based Type-II Quantum DotsBahmani Jalali, Houman; Mohammadi Aria, Mohammad; Dikbas, Ugur Meric; Sadeghi, Sadra; Ganesh Kumar, Baskaran; Sahin, Mehmet; Kavakli, Ibrahim Halil; Ow-Yang, Cleva W.; Nizamoglu, SedatACS Nano (2018), 12 (8), 8104-8114CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Light-induced stimulation of neurons via photoactive surfaces offers rich opportunities for the development of therapeutic methods and high-resoln. retinal prosthetic devices. Quantum dots serve as an attractive building block for such surfaces, as they can be easily functionalized to match the biocompatibility and charge transport requirements of cell stimulation. Although indium-based colloidal quantum dots with type-I band alignment have attracted significant attention as a nontoxic alternative to cadmium-based ones, little attention has been paid to their photovoltaic potential as type-II heterostructures. Herein, we demonstrate type-II indium phosphide/zinc oxide core/shell quantum dots that are incorporated into a photoelectrode structure for neural photostimulation. This induces a hyperpolarizing bioelec. current that triggers the firing of a single neural cell at 4 μW mm-2, 26-fold lower than the ocular safety limit for continuous exposure to visible light. These findings show that nanomaterials can induce a biocompatible and effective biol. junction and can introduce a route in the use of quantum dots in photoelectrode architectures for artificial retinal prostheses.
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70Bahmani Jalali, H.; Karatum, O.; Melikov, R.; Dikbas, U. M.; Sadeghi, S.; Yildiz, E.; Dogru, I. B.; Ozgun Eren, G.; Ergun, C.; Sahin, A.; Kavakli, I. H.; Nizamoglu, S. Biocompatible Quantum Funnels for Neural Photostimulation. Nano Lett. 2019, 19 (9), 5975– 5981, DOI: 10.1021/acs.nanolett.9b01697Google Scholar70https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFCqtbbP&md5=e979d792b0c941e947a986b408223901Biocompatible Quantum Funnels for Neural PhotostimulationBahmani Jalali, Houman; Karatum, Onuralp; Melikov, Rustamzhon; Dikbas, Ugur Meric; Sadeghi, Sadra; Yildiz, Erdost; Dogru, Itir Bakis; Ozgun Eren, Guncem; Ergun, Cagla; Sahin, Afsun; Kavakli, Ibrahim Halil; Nizamoglu, SedatNano Letters (2019), 19 (9), 5975-5981CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Neural photostimulation has high potential to understand the working principles of complex neural networks and develop novel therapeutic methods for neurol. disorders. A key issue in the light-induced cell stimulation is the efficient conversion of light to bioelec. stimuli. In photosynthetic systems developed in millions of years by nature, the absorbed energy by the photoabsorbers is transported via nonradiative energy transfer to the reaction centers. Inspired by these systems, neural interfaces based on biocompatible quantum funnels are developed that direct the photogenerated charge carriers toward the bionanojunction for effective photostimulation. Funnels are constructed with indium-based rainbow quantum dots that are assembled in a graded energy profile. Implementation of a quantum funnel enhances the generated photoelectrochem. current 215% per unit absorbance in comparison with ungraded energy profile in a wireless and free-standing mode and facilitates optical neuromodulation of a single cell. This study indicates that the control of charge transport at nanoscale can lead to unconventional and effective neural interfaces.
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71Srivastava, S. B.; Melikov, R.; Aria, M. M.; Dikbas, U. M.; Kavakli, I. H.; Nizamoglu, S. Band Alignment Engineers Faradaic and Capacitive Photostimulation of Neurons Without Surface Modification. Phys. Rev. Appl. 2019, 11 (4), 044012, DOI: 10.1103/PhysRevApplied.11.044012Google Scholar71https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXpsF2msLw%253D&md5=3a3aa14bb47e3aeaaba9d3ceb47f7cedBand Alignment Engineers Faradaic and Capacitive Photostimulation of Neurons Without Surface ModificationSrivastava, Shashi Bhushan; Melikov, Rustamzhon; Aria, Mohammad Mohammadi; Dikbas, Ugur Meric; Kavakali, Ibrahim Halil; Nizamoglu, SedatPhysical Review Applied (2019), 11 (4), 044012CODEN: PRAHB2; ISSN:2331-7019. (American Physical Society)Photovoltaic substrates have attracted significant attention for neural photostimulation. The control of the Faradaic and capacitive (non-Faradaic) charge transfer mechanisms by these substrates are crit. for safe and effective neural photostimulation. We demonstrate that the intermediate layer can directly control the strength of the capacitive and Faradaic processes under physiol. conditions. To resolve the Faradaic and capacitive stimulations, we enhance photogenerated charge d. levels by incorporating PbS quantum dots into a poly(3-hexylthiophene-2,5-diyl):([6,6]-Phenyl-C61-butyric acid Me ester (P3HT:PCBM) blend. This enhancement stems from the simultaneous increase of absorption, well matched band alignment of PbS quantum dots with P3HT:PCBM, and smaller intermixed phase-sepd. domains with better homogeneity and roughness of the blend. These improvements lead to the photostimulation of neurons at a low light intensity level of 1 mW cm-2, which is within the retinal irradiance level. These findings open up an alternative approach toward superior neural prosthesis.
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72Zunger, A.; Ed, G. Semiconductor Quantum Dots; World Scientific, 1998; Vol. 23. DOI: 10.1557/S0883769400031213Google ScholarThere is no corresponding record for this reference.
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73Winter, J. O.; Gomez, N.; Korgel, B. A.; Schmidt, C. E. Quantum Dots for Electrical Stimulation of Neural Cells. Nanobiophotonics and Biomedical Applications II 2005, 5705, 235, DOI: 10.1117/12.602363Google ScholarThere is no corresponding record for this reference.
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74Colvin, V. L.; Alivisatos, A. P. CdSe Nanocrystals with a Dipole Moment in the First Excited State. J. Chem. Phys. 1992, 97 (1), 730– 733, DOI: 10.1063/1.463573Google Scholar74https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38Xlt1amtbY%253D&md5=74d470577f820d2797af76f38b35656dCadmium selenide nanocrystals with a dipole moment in the first excited stateColvin, V. L.; Alivisatos, A. P.Journal of Chemical Physics (1992), 97 (1), 730-3CODEN: JCPSA6; ISSN:0021-9606.The Stark effect was used to demonstrate that the first electronic state in CdSe nanocrystals has significant dipolar character. The Stark effect spectrum of CdSe crystallites embedded in polymethylmethacrylate at 100 K is given. The UV-visible spectra is also shown. The field dependence of the Stark effect signal is shown and exhibits quadratic behavior. The authors propose that the line shape results from a change in the dipole moment upon electronic excitation.
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75SCHULTZ, S. K. Principles of Neural Science, 4th Ed. Am. J. Psychiatry 2001, 158 (4), 662– 662, DOI: 10.1176/appi.ajp.158.4.662Google ScholarThere is no corresponding record for this reference.
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76Chen, C.; Wu, Y.; Liu, L.; Gao, Y.; Chen, X.; Bi, W.; Chen, X.; Liu, D.; Dai, Q.; Song, H. Interfacial Engineering and Photon Downshifting of CsPbBr3 Nanocrystals for Efficient, Stable, and Colorful Vapor Phase Perovskite Solar Cells. Adv. Sci. 2019, 6 (11), 1802046, DOI: 10.1002/advs.201802046Google Scholar76https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3M3kslOkuw%253D%253D&md5=071477208ff5f7081d56d86edae2e657Interfacial Engineering and Photon Downshifting of CsPbBr3 Nanocrystals for Efficient, Stable, and Colorful Vapor Phase Perovskite Solar CellsChen Cong; Wu Yanjie; Liu Le; Gao Yanbo; Chen Xinfu; Bi Wenbo; Chen Xu; Liu Dali; Song Hongwei; Dai QilinAdvanced science (Weinheim, Baden-Wurttemberg, Germany) (2019), 6 (11), 1802046 ISSN:2198-3844.Photovoltaic devices employing lead halide perovskites as the photoactive layer have attracted enormous attention due to their commercialization potential. Yet, there exists challenges on the way to the practical use of perovskite solar cells (PSCs), such as light stability and current-voltage (J-V ) hysteresis. Inorganic perovskite nanocrystals (IPNCs) are promising candidates for high-performance photovoltaic devices due to their simple synthesis methods, tunable bandgap, and efficient photon downshifting effect for ultraviolet (UV) light blocking and conversion. In this work, CsPbBr3 IPNCs modification could give rise to the vapor phase and solution-processed PSCs with a power conversion efficiency (PCE) of 16.4% and 20.8%, respectively, increased by 11.6% and 5.6% compared to the control devices for more efficient UV utilization and carrier recombination suppression. As far as is known, 11.6% is the most effective enhanced factor for PSCs based on photon downshifting effect inside of devices. The CsPbBr3 layer could also significantly retard light-induced degradation, leading to the lifetime over 100 h under UV illumination for PSCs. Additionally, the modified PSCs exhibit weak hysteresis and multiple colors of fluorescence. These results shed light on the future design of combining a photon downshifting layer and carrier interfacial modification layer in the applications of perovskite optoelectronic devices.
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77Carey, G. H.; Abdelhady, A. L.; Ning, Z.; Thon, S. M.; Bakr, O. M.; Sargent, E. H. Colloidal Quantum Dot Solar Cells. Chem. Rev. 2015, 115 (23), 12732– 12763, DOI: 10.1021/acs.chemrev.5b00063Google Scholar77https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtVKitLzL&md5=757fcd30bf9b7fe70d44cfbd4f28e5adColloidal Quantum Dot Solar CellsCarey, Graham H.; Abdelhady, Ahmed L.; Ning, Zhijun; Thon, Susanna M.; Bakr, Osman M.; Sargent, Edward H.Chemical Reviews (Washington, DC, United States) (2015), 115 (23), 12732-12763CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)This review focuses on the application of colloidal quantum dots in photovoltaic devices. We survey the fabrication process, start to finish, addressing advances in synthesis methods, phys. and chem. materials processing procedures, quantification and improvement of optoelectronic properties, and device architecture and performance. This survey addresses the key challenges facing the field: synthesizing high-quality quantum dot solns. with ideal properties (band gap, absorption, monodispersity), converting these solns. into high-quality CQD films (with ideal quantum dot packing, surface passivation, and absorptive/conductive properties), and constructing an ideal material stack around the CQD film to maximize overall device efficiency.
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78Cho, Y.; Hou, B.; Lim, J.; Lee, S.; Pak, S.; Hong, J.; Giraud, P.; Jang, A. R.; Lee, Y. W.; Lee, J.; Jang, J. E.; Snaith, H. J.; Morris, S. M.; Sohn, J. I.; Cha, S.; Kim, J. M. Balancing Charge Carrier Transport in a Quantum Dot P-N Junction toward Hysteresis-Free High-Performance Solar Cells. ACS Energy Lett. 2018, 3 (4), 1036– 1043, DOI: 10.1021/acsenergylett.8b00130Google Scholar78https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXmslOns7g%253D&md5=f2477028fce82d8003a2079c4bf2dd8bBalancing Charge Carrier Transport in a Quantum Dot P-N Junction toward Hysteresis-Free High-Performance Solar CellsCho, Yuljae; Hou, Bo; Lim, Jongchul; Lee, Sanghyo; Pak, Sangyeon; Hong, John; Giraud, Paul; Jang, A.-Rang; Lee, Young-Woo; Lee, Juwon; Jang, Jae Eun; Snaith, Henry J.; Morris, Stephen M.; Sohn, Jung Inn; Cha, Seung Nam; Kim, Jong MinACS Energy Letters (2018), 3 (4), 1036-1043CODEN: AELCCP; ISSN:2380-8195. (American Chemical Society)In a quantum dot solar cell (QDSC) that has an inverted structure, the QD layers form two different junctions between the electron transport layer (ETL) and the other semiconducting QD layer. Recent work on an inverted-structure QDSC has revealed that the junction between the QD layers is the dominant junction, rather than the junction between the ETL and the QD layers, which is in contrast to the conventional wisdom. However, to date, there have been a lack of systematic studies on the role and importance of the QD heterojunction structure on the behavior of the solar cell and the resulting device performance. In this study, we have systematically controlled the structure of the QD junction to balance charge transport, which demonstrates that the position of the junction has a significant effect on the hysteresis effect, fill factor, and solar cell performance and is attributed to balanced charge transport.
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79Hong, J.; Hou, B.; Lim, J.; Pak, S.; Kim, B. S.; Cho, Y.; Lee, J.; Lee, Y. W.; Giraud, P.; Lee, S.; Park, J. B.; Morris, S. M.; Snaith, H. J.; Sohn, J. I.; Cha, S. N.; Kim, J. M. Enhanced Charge Carrier Transport Properties in Colloidal Quantum Dot Solar Cells via Organic and Inorganic Hybrid Surface Passivation. J. Mater. Chem. A 2016, 4 (48), 18769– 18775, DOI: 10.1039/C6TA06835AGoogle Scholar79https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhs1CgtbvP&md5=b6050e3228151f60145c8df1b5a48787Enhanced charge carrier transport properties in colloidal quantum dot solar cells via organic and inorganic hybrid surface passivationHong, John; Hou, Bo; Lim, Jongchul; Pak, Sangyeon; Kim, Byung-Sung; Cho, Yuljae; Lee, Juwon; Lee, Young-Woo; Giraud, Paul; Lee, Sanghyo; Park, Jong Bae; Morris, Stephen M.; Snaith, Henry J.; Sohn, Jung Inn; Cha, SeungNam; Kim, Jong MinJournal of Materials Chemistry A: Materials for Energy and Sustainability (2016), 4 (48), 18769-18775CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)Colloidal quantum dots (CQDs) are extremely promising as photovoltaic materials. In particular, the tunability of their electronic band gap and cost effective synthetic procedures allow for the versatile fabrication of solar energy harvesting cells, resulting in optimal device performance. However, one of the main challenges in developing high performance quantum dot solar cells (QDSCs) is the improvement of the photo-generated charge transport and collection, which is mainly hindered by imperfect surface functionalization, such as the presence of surface electronic trap sites and the initial bulky surface ligands. Therefore, for these reasons, finding effective methods to efficiently decorate the surface of the as-prepd. CQDs with new short mol. length chem. structures so as to enhance the performance of QDSCs is highly desirable. Here, we suggest employing hybrid halide ions along with the shortest heterocyclic mol. as a robust passivation structure to eliminate surface trap sites while decreasing the charge trapping dynamics and increasing the charge extn. efficiency in CQD active layers. This hybrid ligand treatment shows a better coordination with Pb atoms within the crystal, resulting in low trap sites and a near perfect removal of the pristine initial bulky ligands, thereby achieving better cond. and film structure. Compared to halide ion-only treated cells, solar cells fabricated through this hybrid passivation method show an increase in the power conversion efficiency from 5.3% for the halide ion-treated cells to 6.8% for the hybrid-treated solar cells.
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80Gao, J.; Jeong, S.; Lin, F.; Erslev, P. T.; Semonin, O. E.; Luther, J. M.; Beard, M. C. Improvement in Carrier Transport Properties by Mild Thermal Annealing of PbS Quantum Dot Solar Cells. Appl. Phys. Lett. 2013, 102 (4), 043506, DOI: 10.1063/1.4789434Google Scholar80https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFaisbc%253D&md5=73e83f273e4316d7dcd5b49371197281Improvement in carrier transport properties by mild thermal annealing of PbS quantum dot solar cellsGao, Jianbo; Jeong, Sohee; Lin, Feng; Erslev, Peter T.; Semonin, Octavi E.; Luther, Joseph M.; Beard, Matthew C.Applied Physics Letters (2013), 102 (4), 043506/1-043506/5CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)We studied the effect of post-deposition thermal annealing in the prepn. of PbS quantum dot solar cells. We find an optimal annealing temp. that improves the power conversion efficiency by a factor of 1.5 for different sized quantum dots with bandgaps of 1.65 and 1.27 eV. We examd. the onset of the photocurrent response and correlated that with domain grain growth and find that annealing the PbS quantum dot array at 120° causes little change in the PbS quantum dot size, bandgap, and open-circuit voltage and yet leads to an increase in the carrier transport as realized by an improved current response. We also find a decrease in the activation energy of a shallow trap, which also likely contributes to the improvement in the solar cell efficiency. (c) 2013 American Institute of Physics.
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81Brovelli, S.; Schaller, R. D.; Crooker, S. A.; García-Santamaría, F.; Chen, Y.; Viswanatha, R.; Hollingsworth, J. A.; Htoon, H.; Klimov, V. I. Nano-Engineered Electron-Hole Exchange Interaction Controls Exciton Dynamics in Core-Shell Semiconductor Nanocrystals. Nat. Commun. 2011, 2 (1), 280, DOI: 10.1038/ncomms1281Google Scholar81https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3MvkvFWqug%253D%253D&md5=cd156656ed94ca5ccf79b41c5063c31aNano-engineered electron-hole exchange interaction controls exciton dynamics in core-shell semiconductor nanocrystalsBrovelli S; Schaller R D; Crooker S A; Garcia-Santamaria F; Chen Y; Viswanatha R; Hollingsworth J A; Htoon H; Klimov V INature communications (2011), 2 (), 280 ISSN:.A strong electron-hole exchange interaction (EI) in semiconductor nanocrystals (NCs) gives rise to a large (up to tens of meV) splitting between optically active ('bright') and optically passive ('dark') excitons. This dark-bright splitting has a significant effect on the optical properties of band-edge excitons and leads to a pronounced temperature and magnetic field dependence of radiative decay. Here we demonstrate a nanoengineering-based approach that provides control over EI while maintaining nearly constant emission energy. We show that the dark-bright splitting can be widely tuned by controlling the electron-hole spatial overlap in core-shell CdSe/CdS NCs with a variable shell width. In thick-shell samples, the EI energy reduces to <250 μeV, which yields a material that emits with a nearly constant rate over temperatures from 1.5 to 300 K and magnetic fields up to 7 T. The EI-manipulation strategies demonstrated here are general and can be applied to other nanostructures with variable electron-hole overlap.
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82Meinardi, F.; Colombo, A.; Velizhanin, K. A.; Simonutti, R.; Lorenzon, M.; Beverina, L.; Viswanatha, R.; Klimov, V. I.; Brovelli, S. Large-Area Luminescent Solar Concentrators Based on Stokes-Shift-Engineered Nanocrystals in a Mass-Polymerized PMMA Matrix. Nat. Photonics 2014, 8 (5), 392– 399, DOI: 10.1038/nphoton.2014.54Google Scholar82https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmtlWqsbg%253D&md5=cfa9667bf689b3f506ee0c26368f98efLarge-area luminescent solar concentrators based on 'Stokes-shift-engineered' nanocrystals in a mass-polymerized PMMA matrixMeinardi, Francesco; Colombo, Annalisa; Velizhanin, Kirill A.; Simonutti, Roberto; Lorenzon, Monica; Beverina, Luca; Viswanatha, Ranjani; Klimov, Victor I.; Brovelli, SergioNature Photonics (2014), 8 (5), 392-399CODEN: NPAHBY; ISSN:1749-4885. (Nature Publishing Group)Luminescent solar concentrators are cost-effective complements to semiconductor photovoltaics that can boost the output of solar cells and allow for the integration of photovoltaic-active architectural elements into buildings (for example, photovoltaic windows). Colloidal quantum dots are attractive for use in luminescent solar concentrators, but their small Stokes shift results in reabsorption losses that hinder the realization of large-area devices. Here, we use 'Stokes-shift-engineered' CdSe/CdS quantum dots with giant shells (giant quantum dots) to realize luminescent solar concentrators without reabsorption losses for device dimensions up to tens of centimeters. Monte-Carlo simulations show a 100-fold increase in efficiency using giant quantum dots compared with core-only nanocrystals. We demonstrate the feasibility of this approach by using high-optical-quality quantum dot-polymethylmethacrylate nanocomposites fabricated using a modified industrial method that preserves the light-emitting properties of giant quantum dots upon incorporation into the polymer. Study of these luminescent solar concentrators yields optical efficiencies >10% and an effective concn. factor of 4.4. These results demonstrate the significant promise of Stokes-shift-engineered quantum dots for large-area luminescent solar concentrators.
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83Karatum, O.; Eren, G. O.; Melikov, R.; Onal, A.; Ow-Yang, C. W.; Sahin, M.; Nizamoglu, S. Quantum Dot and Electron Acceptor Nano-Heterojunction for Photo-Induced Capacitive Charge-Transfer. Sci. Rep. 2021, 11 (1), 1– 9, DOI: 10.1038/s41598-021-82081-yGoogle ScholarThere is no corresponding record for this reference.
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84Kumsa, D. W.; Bhadra, N.; Hudak, E. M.; Kelley, S. C.; Untereker, D. F.; Mortimer, J. T. Electron Transfer Processes Occurring on Platinum Neural Stimulating Electrodes: A Tutorial on the i(V e) Profile. J. Neural Eng. 2016, 13 (5), 052001, DOI: 10.1088/1741-2560/13/5/052001Google Scholar84https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2szgtlGgtw%253D%253D&md5=0e743a4eb1a4752a9b84c128504a2d1eElectron transfer processes occurring on platinum neural stimulating electrodes: a tutorial on the i(V e) profileKumsa Doe W; Bhadra Narendra; Hudak Eric M; Kelley Shawn C; Untereker Darrel F; Mortimer J ThomasJournal of neural engineering (2016), 13 (5), 052001 ISSN:.The aim of this tutorial is to encourage members of the neuroprosthesis community to incorporate electron transfer processes into their thinking and provide them with the tools to do so when they design and work with neurostimulating devices. The focus of this article is on platinum because it is the most used electrode metal for devices in commercial use. The i(V e) profile or cyclic voltammogram contains information about electron transfer processes that can occur when the electrode-electrolyte interface, V e, is at a specific potential, and assumed to be near steady-state conditions. For the engineer/designer this means that if the potential is not in the range of a specific electron transfer process, that process cannot occur. An i(V e) profile, recorded at sweep rates greater than 0.1 mVs(-1), approximates steady-state conditions. Rapid transient potential excursions, like that seen with neural stimulation pulses, may be too fast for the reaction to occur, however, this means that if the potential is in the range of a specific electron transfer process it may occur and should be considered. The approach described here can be used to describe the thermodynamic electron transfer processes on other candidate electrode metals, e.g. stainless steel, iridium, carbon-based, etc.
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85Merrill, D. R.; Bikson, M.; Jefferys, J. G. R. Electrical Stimulation of Excitable Tissue: Design of Efficacious and Safe Protocols. J. Neurosci. Methods 2005, 141 (2), 171– 198, DOI: 10.1016/j.jneumeth.2004.10.020Google Scholar85https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD2M%252FjsVOkug%253D%253D&md5=a4e690038eaa8524f9fc557dfb9e43a4Electrical stimulation of excitable tissue: design of efficacious and safe protocolsMerrill Daniel R; Bikson Marom; Jefferys John G RJournal of neuroscience methods (2005), 141 (2), 171-98 ISSN:0165-0270.The physical basis for electrical stimulation of excitable tissue, as used by electrophysiological researchers and clinicians in functional electrical stimulation, is presented with emphasis on the fundamental mechanisms of charge injection at the electrode/tissue interface. Faradaic and non-Faradaic charge transfer mechanisms are presented and contrasted. An electrical model of the electrode/tissue interface is given. The physical basis for the origin of electrode potentials is given. Various methods of controlling charge delivery during pulsing are presented. Electrochemical reversibility is discussed. Commonly used electrode materials and stimulation protocols are reviewed in terms of stimulation efficacy and safety. Principles of stimulation of excitable tissue are reviewed with emphasis on efficacy and safety. Mechanisms of damage to tissue and the electrode are reviewed.
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86Kumsa, D. W.; Bhadra, N.; Hudak, E. M.; Kelley, S. C.; Untereker, D. F.; Mortimer, J. T. Electron Transfer Processes Occurring on Platinum Neural Stimulating Electrodes: A Tutorial on Thei(Ve) Profile. J. Neural Eng. 2016, 13 (5), 052001, DOI: 10.1088/1741-2560/13/5/052001Google Scholar86https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2szgtlGgtw%253D%253D&md5=0e743a4eb1a4752a9b84c128504a2d1eElectron transfer processes occurring on platinum neural stimulating electrodes: a tutorial on the i(V e) profileKumsa Doe W; Bhadra Narendra; Hudak Eric M; Kelley Shawn C; Untereker Darrel F; Mortimer J ThomasJournal of neural engineering (2016), 13 (5), 052001 ISSN:.The aim of this tutorial is to encourage members of the neuroprosthesis community to incorporate electron transfer processes into their thinking and provide them with the tools to do so when they design and work with neurostimulating devices. The focus of this article is on platinum because it is the most used electrode metal for devices in commercial use. The i(V e) profile or cyclic voltammogram contains information about electron transfer processes that can occur when the electrode-electrolyte interface, V e, is at a specific potential, and assumed to be near steady-state conditions. For the engineer/designer this means that if the potential is not in the range of a specific electron transfer process, that process cannot occur. An i(V e) profile, recorded at sweep rates greater than 0.1 mVs(-1), approximates steady-state conditions. Rapid transient potential excursions, like that seen with neural stimulation pulses, may be too fast for the reaction to occur, however, this means that if the potential is in the range of a specific electron transfer process it may occur and should be considered. The approach described here can be used to describe the thermodynamic electron transfer processes on other candidate electrode metals, e.g. stainless steel, iridium, carbon-based, etc.
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87Lai, B.-C.; Wu, J.-G.; Luo, S.-C. Revisiting Background Signals and the Electrochemical Windows of Au, Pt, and GC Electrodes in Biological Buffers. ACS Appl. Energy Mater. 2019, 2 (9), 6808– 6816, DOI: 10.1021/acsaem.9b01249Google Scholar87https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFKhsr7I&md5=5d4d8935b3f49ced481f325f5a69c894Revisiting Background Signals and the Electrochemical Windows of Au, Pt, and GC Electrodes in Biological BuffersLai, Bo-Chang; Wu, Jhih-Guang; Luo, Shyh-ChyangACS Applied Energy Materials (2019), 2 (9), 6808-6816CODEN: AAEMCQ; ISSN:2574-0962. (American Chemical Society)For electrochem. expts. involving biol. buffers, pH values, ions, and electrode materials play major roles in the electrochem. readout of the measurements. When conducting electrochem. expts., background signals are sometimes mixed with true signals, easily leading to a wrong interpretation of the data. These background signals are easily induced by the reactions between buffers and electrode materials. However, these background signals have rarely been studied systematically. In response to rapid developments in the field and application of bioelectrodes, the authors conducted a much-needed systematic study of these background signals and the electrochem. windows in buffers-specifically, of the electrochem. windows Au, glassy C, and Pt in three most commonly used biol. buffers, namely, Tris, HEPES, and phosphate. The authors examd. the pH effect using HCl, H2SO4, and NaOH to modulate the pH values from 6.0 to 9.0 in the three buffers. Also, through comparison of HCl and H2SO4, the authors were able to illustrate the reaction between Cl- ions and the metallic electrode. This reaction also led to clear redox peaks as background signals in cyclic voltammograms. When a high potential was applied, the formation of hydroxide was evident on the metallic electrode, which led to a clear redn. peak in cyclic voltammograms. The authors used an at. force microscope to monitor the morphol. of the electrode surface when a cyclic potential was applied. All tests were conducted in the presence of 100 mM LiClO4, which was used as the electrolytes. These characterization results yield crit. insights into electrode surface reactions, insights which are crucial for precisely interpreting electrochem. results measured in biol. buffers. This fundamental study provides comprehensive information, which is esp. helpful for the development of bioelectrode materials and bioelectronics applications.
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88Karatum, O.; Aria, M. M.; Eren, G. O.; Yildiz, E.; Melikov, R.; Srivastava, S. B.; Surme, S.; Dogru, I. B.; Bahmani Jalali, H.; Ulgut, B.; Sahin, A.; Kavakli, I. H.; Nizamoglu, S. Nanoengineering InP Quantum Dot-Based Photoactive Biointerfaces for Optical Control of Neurons. Frontiers in Neuroscience. 2021, 15, 724, DOI: 10.3389/fnins.2021.652608Google ScholarThere is no corresponding record for this reference.
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89Massobrio, P.; Massobrio, G.; Martinoia, S. Interfacing Cultured Neurons to Microtransducers Arrays: A Review of the Neuro-Electronic Junction Models. Frontiers in Neuroscience. 2016, 10, 282, DOI: 10.3389/fnins.2016.00282Google Scholar89https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2s3jsVeiug%253D%253D&md5=ac4bf3a4f52bcee0d3f0bd764cff5aecInterfacing Cultured Neurons to Microtransducers Arrays: A Review of the Neuro-Electronic Junction ModelsMassobrio Paolo; Massobrio Giuseppe; Martinoia SergioFrontiers in neuroscience (2016), 10 (), 282 ISSN:1662-4548.Microtransducer arrays, both metal microelectrodes and silicon-based devices, are widely used as neural interfaces to measure, extracellularly, the electrophysiological activity of excitable cells. Starting from the pioneering works at the beginning of the 70's, improvements in manufacture methods, materials, and geometrical shape have been made. Nowadays, these devices are routinely used in different experimental conditions (both in vivo and in vitro), and for several applications ranging from basic research in neuroscience to more biomedical oriented applications. However, the use of these micro-devices deeply depends on the nature of the interface (coupling) between the cell membrane and the sensitive active surface of the microtransducer. Thus, many efforts have been oriented to improve coupling conditions. Particularly, in the latest years, two innovations related to the use of carbon nanotubes as interface material and to the development of micro-structures which can be engulfed by the cell membrane have been proposed. In this work, we review what can be simulated by using simple circuital models and what happens at the interface between the sensitive active surface of the microtransducer and the neuronal membrane of in vitro neurons. We finally focus our attention on these two novel technological solutions capable to improve the coupling between neuron and micro-nano transducer.
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90Lyu, Y.; Xie, C.; Chechetka, S. A.; Miyako, E.; Pu, K. Semiconducting Polymer Nanobioconjugates for Targeted Photothermal Activation of Neurons. J. Am. Chem. Soc. 2016, 138 (29), 9049– 9052, DOI: 10.1021/jacs.6b05192Google Scholar90https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFGjs7zK&md5=c7a7f85e6472a2fc3f0f54c48d1692f8Semiconducting Polymer Nanobioconjugates for Targeted Photothermal Activation of NeuronsLyu, Yan; Xie, Chen; Chechetka, Svetlana A.; Miyako, Eijiro; Pu, KanyiJournal of the American Chemical Society (2016), 138 (29), 9049-9052CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Optogenetics provides powerful means for precise control of neuronal activity; however, the requirement of transgenesis and the incapability to extend the neuron excitation window into the deep-tissue-penetrating near-IR (NIR) region partially limit its application. We herein report a potential alternative approach to optogenetics using semiconducting polymer nanobioconjugates (SPNsbc) as the photothermal nanomodulator to control the thermosensitive ion channels in neurons. SPNsbc are designed to efficiently absorb the NIR light at 808 nm and have a photothermal conversion efficiency higher than that of gold nanorods. By virtue of the fast heating capability in conjunction with the precise targeting to the thermosensitive ion channel, SPNsbc can specifically and rapidly activate the intracellular Ca2+ influx of neuronal cells in a reversible and safe manner. Our study provides an org. nanoparticle based strategy that eliminates the need for genetic transfection to remotely regulate cellular machinery.
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91Shapiro, M. G.; Homma, K.; Villarreal, S.; Richter, C. P.; Bezanilla, F. Infrared Light Excites Cells by Changing Their Electrical Capacitance. Nat. Commun. 2012, 3, 736, DOI: 10.1038/ncomms1742Google Scholar91https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC38zhtVKlsg%253D%253D&md5=6148b65fe61a9f3e31dd4f25edf7f424Infrared light excites cells by changing their electrical capacitanceShapiro Mikhail G; Homma Kazuaki; Villarreal Sebastian; Richter Claus-Peter; Bezanilla FranciscoNature communications (2012), 3 (), 736 ISSN:.Optical stimulation has enabled important advances in the study of brain function and other biological processes, and holds promise for medical applications ranging from hearing restoration to cardiac pace making. In particular, pulsed laser stimulation using infrared wavelengths >1.5 μm has therapeutic potential based on its ability to directly stimulate nerves and muscles without any genetic or chemical pre-treatment. However, the mechanism of infrared stimulation has been a mystery, hindering its path to the clinic. Here we show that infrared light excites cells through a novel, highly general electrostatic mechanism. Infrared pulses are absorbed by water, producing a rapid local increase in temperature. This heating reversibly alters the electrical capacitance of the plasma membrane, depolarizing the target cell. This mechanism is fully reversible and requires only the most basic properties of cell membranes. Our findings underscore the generality of pulsed infrared stimulation and its medical potential.
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92Wang, L. V.; Hu, S. Photoacoustic Tomography: In Vivo Imaging from Organelles to Organs. Science (80-.). 2012, 335 (6075), 1458– 1462, DOI: 10.1126/science.1216210Google Scholar92https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XktFWktrw%253D&md5=667dfb771b1bed8da79f60f354b0c988Photoacoustic Tomography: In Vivo Imaging from Organelles to OrgansWang, Lihong V.; Hu, SongScience (Washington, DC, United States) (2012), 335 (6075), 1458-1462CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Photoacoustic tomog. (PAT) can create multiscale multicontrast images of living biol. structures ranging from organelles to organs. This emerging technol. overcomes the high degree of scattering of optical photons in biol. tissue by making use of the photoacoustic effect. Light absorption by mols. creates a thermally induced pressure jump that launches ultrasonic waves, which are received by acoustic detectors to form images. Different implementations of PAT allow the spatial resoln. to be scaled with the desired imaging depth in tissue while a high depth-to-resoln. ratio is maintained. As a rule of thumb, the achievable spatial resoln. is on the order of 1/200 of the desired imaging depth, which can reach up to 7 cm. PAT provides anatomical, functional, metabolic, mol., and genetic contrasts of vasculature, hemodynamics, oxygen metab., biomarkers, and gene expression. We review the state of the art of PAT for both biol. and clin. studies and discuss future prospects.
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93Jiang, Y.; Carvalho-De-Souza, J. L.; Wong, R. C. S.; Luo, Z.; Isheim, D.; Zuo, X.; Nicholls, A. W.; Jung, I. W.; Yue, J.; Liu, D. J.; Wang, Y.; De Andrade, V.; Xiao, X.; Navrazhnykh, L.; Weiss, D. E.; Wu, X.; Seidman, D. N.; Bezanilla, F.; Tian, B. Heterogeneous Silicon Mesostructures for Lipid-Supported Bioelectric Interfaces. Nat. Mater. 2016, 15 (9), 1023– 1030, DOI: 10.1038/nmat4673Google Scholar93https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVKhsrfE&md5=9e770976afe38388e12fece2f94b0396Heterogeneous silicon mesostructures for lipid-supported bioelectric interfacesJiang, Yuanwen; Carvalho-de-Souza, Joao L.; Wong, Raymond C. S.; Luo, Zhiqiang; Isheim, Dieter; Zuo, Xiaobing; Nicholls, Alan W.; Jung, Il Woong; Yue, Jiping; Liu, Di-Jia; Wang, Yucai; De Andrade, Vincent; Xiao, Xianghui; Navrazhnykh, Luizetta; Weiss, Dara E.; Wu, Xiaoyang; Seidman, David N.; Bezanilla, Francisco; Tian, BozhiNature Materials (2016), 15 (9), 1023-1030CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)Silicon-based materials have widespread application as biophys. tools and biomedical devices. Here the authors introduce a biocompatible and degradable mesostructured form of silicon with multi-scale structural and chem. heterogeneities. The material was synthesized using mesoporous silica as a template through a CVD process. It has an amorphous at. structure, an ordered nanowire-based framework and random submicrometer voids, and shows an av. Young's modulus that is 2-3 orders of magnitude smaller than that of single-cryst. silicon. In addn., the authors used the heterogeneous silicon mesostructures to design a lipid-bilayer-supported bioelec. interface that is remotely controlled and temporally transient, and that permits non-genetic and subcellular optical modulation of the electrophysiol. dynamics in single dorsal root ganglia neurons. The authors' findings suggest that the biomimetic expansion of silicon into heterogeneous and deformable forms can open up opportunities in extracellular biomaterial or bioelec. systems.
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94Carvalho-de-Souza, J. L.; Treger, J. S.; Dang, B.; Kent, S. B. H.; Pepperberg, D. R.; Bezanilla, F. Photosensitivity of Neurons Enabled by Cell-Targeted Gold Nanoparticles. Neuron 2015, 86 (1), 207– 217, DOI: 10.1016/j.neuron.2015.02.033Google Scholar94https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksVaisrY%253D&md5=bfcc67e0facd325061fbd58fd45cbad3Photosensitivity of Neurons Enabled by Cell-Targeted Gold NanoparticlesCarvalho-de-Souza, Joao L.; Treger, Jeremy S.; Dang, Bobo; Kent, Stephen B. H.; Pepperberg, David R.; Bezanilla, FranciscoNeuron (2015), 86 (1), 207-217CODEN: NERNET; ISSN:0896-6273. (Cell Press)Unmodified neurons can be directly stimulated with light to produce action potentials, but such techniques have lacked localization of the delivered light energy. Here we show that gold nanoparticles can be conjugated to high-avidity ligands for a variety of cellular targets. Once bound to a neuron, these particles transduce millisecond pulses of light into heat, which changes membrane capacitance, depolarizing the cell and eliciting action potentials. Compared to non-functionalized nanoparticles, ligand-conjugated nanoparticles highly resist convective washout and enable photothermal stimulation with lower delivered energy and resulting temp. increase. Ligands targeting three different membrane proteins were tested; all showed similar activity and washout resistance. This suggests that many types of ligands can be bound to nanoparticles, preserving ligand and nanoparticle function, and that many different cell phenotypes can be targeted by appropriate choice of ligand. The findings have applications as an alternative to optogenetics and potentially for therapies involving neuronal photostimulation.
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95Rastogi, S. K.; Garg, R.; Scopelliti, M. G.; Pinto, B. I.; Hartung, J. E.; Kim, S.; Murphey, C. G. E.; Johnson, N.; San Roman, D.; Bezanilla, F. Remote Nongenetic Optical Modulation of Neuronal Activity Using Fuzzy Graphene. Proc. Natl. Acad. Sci. U. S. A. 2020, 117 (24), 13339– 13349, DOI: 10.1073/pnas.1919921117Google Scholar95https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtF2jtL7I&md5=ef088ad3a31790b61f3e002e6bf67ee6Remote nongenetic optical modulation of neuronal activity using fuzzy grapheneRastogi, Sahil K.; Garg, Raghav; Scopelliti, Matteo Giuseppe; Pinto, Bernardo I.; Hartung, Jane E.; Kim, Seokhyoung; Murphey, Corban G. E.; Johnson, Nicholas; Roman, Daniel San; Bezanilla, Francisco; Cahoon, James F.; Gold, Michael S.; Chamanzar, Maysam; Cohen-Karni, TzahiProceedings of the National Academy of Sciences of the United States of America (2020), 117 (24), 13339-13349CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The ability to modulate cellular electrophysiol. is fundamental to the investigation of development, function, and disease. Currently, there is a need for remote, nongenetic, light-induced control of cellular activity in two-dimensional (2D) and three-dimensional (3D) platforms. Here, we report a breakthrough hybrid nanomaterial for remote, nongenetic, photothermal stimulation of 2D and 3D neural cellular systems. We combine one-dimensional (1D) nanowires (NWs) and 2D graphene flakes grown out-of-plane for highly controlled photothermal stimulation at subcellular precision without the need for genetic modification, with laser energies lower than a hundred nanojoules, one to two orders of magnitude lower than Au-, C-, and Si-based nanomaterials. Photothermal stimulation using NW-templated 3D fuzzy graphene (NT-3DFG) is flexible due to its broadband absorption and does not generate cellular stress. Therefore, it serves as a powerful toolset for studies of cell signaling within and between tissues and can enable therapeutic interventions.
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96Martino, N.; Feyen, P.; Porro, M.; Bossio, C.; Zucchetti, E.; Ghezzi, D.; Benfenati, F.; Lanzani, G.; Antognazza, M. R. Photothermal Cellular Stimulation in Functional Bio-Polymer Interfaces. Sci. Rep. 2015, 5, 1– 8, DOI: 10.1038/srep08911Google ScholarThere is no corresponding record for this reference.
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97Jiang, Y.; Lee, H. J.; Lan, L.; Tseng, H. an; Yang, C.; Man, H. Y.; Han, X.; Cheng, J. X. Optoacoustic Brain Stimulation at Submillimeter Spatial Precision. Nat. Commun. 2020, 11 (1), 1– 9, DOI: 10.1038/s41467-020-14706-1Google ScholarThere is no corresponding record for this reference.
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98Shi, L.; Jiang, Y.; Fernandez, F. R.; Chen, G.; Lan, L.; Man, H.-Y.; White, J. A.; Cheng, J.-X.; Yang, C. Non-Genetic Photoacoustic Stimulation of Single Neurons by a Tapered Fiber Optoacoustic Emitter. Light Sci. Appl. 2021, 10 (1), 143, DOI: 10.1038/s41377-021-00580-zGoogle Scholar98https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhsFGgt7bF&md5=9a9ba0e6c81f5152e368e74f26aa16a8Non-genetic photoacoustic stimulation of single neurons by a tapered fiber optoacoustic emitterShi, Linli; Jiang, Ying; Fernandez, Fernando R.; Chen, Guo; Lan, Lu; Man, Heng-Ye; White, John A.; Cheng, Ji-Xin; Yang, ChenLight: Science & Applications (2021), 10 (1), 143CODEN: LSAIAZ; ISSN:2047-7538. (Nature Research)Abstr.: Neuromodulation at high spatial resoln. poses great significance in advancing fundamental knowledge in the field of neuroscience and offering novel clin. treatments. Here, we developed a tapered fiber optoacoustic emitter (TFOE) generating an ultrasound field with a high spatial precision of 39.6 μm, enabling optoacoustic activation of single neurons or subcellular structures, such as axons and dendrites. Temporally, a single acoustic pulse of sub-microsecond converted by the TFOE from a single laser pulse of 3 ns is shown as the shortest acoustic stimuli so far for successful neuron activation. The precise ultrasound generated by the TFOE enabled the integration of the optoacoustic stimulation with highly stable patch-clamp recording on single neurons. Direct measurements of the elec. response of single neurons to acoustic stimulation, which is difficult for conventional ultrasound stimulation, have been demonstrated. By coupling TFOE with ex vivo brain slice electrophysiol., we unveil cell-type-specific responses of excitatory and inhibitory neurons to acoustic stimulation. These results demonstrate that TFOE is a non-genetic single-cell and sub-cellular modulation technol., which could shed new insights into the mechanism of ultrasound neurostimulation.
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99Tao, W.; Ji, X.; Xu, X.; Islam, M. A.; Li, Z.; Chen, S.; Saw, P. E.; Zhang, H.; Bharwani, Z.; Guo, Z.; Shi, J.; Farokhzad, O. C. Antimonene Quantum Dots: Synthesis and Application as Near-Infrared Photothermal Agents for Effective Cancer Therapy. Angew. Chemie Int. Ed. 2017, 56 (39), 11896– 11900, DOI: 10.1002/anie.201703657Google Scholar99https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFOlt7bN&md5=1fa6db1268d20d3e07d4553cb69e896cAntimonene quantum dots: Synthesis and application as near-infrared photothermal agents for effective cancer therapyTao, Wei; Ji, Xiaoyuan; Xu, Xiaoding; Islam, Mohammad Ariful; Li, Zhongjun; Chen, Si; Saw, Phei Er; Zhang, Han; Bharwani, Zameer; Guo, Zilei; Shi, Jinjun; Farokhzad, Omid C.Angewandte Chemie, International Edition (2017), 56 (39), 11896-11900CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Photothermal therapy (PTT) has shown significant potential for cancer therapy. However, developing nanomaterials (NMs)-based photothermal agents (PTAs) with satisfactory photothermal conversion efficacy (PTCE) and biocompatibility remains a key challenge. Herein, a new generation of PTAs based on two-dimensional (2D) antimonene quantum dots (AMQDs) was developed by a novel liq. exfoliation method. Surface modification of AMQDs with polyethylene glycol (PEG) significantly enhanced both biocompatibility and stability in physiol. medium. The PEG-coated AMQDs showed a PTCE of 45.5 %, which is higher than many other NMs-based PTAs such as graphene, Au, MoS2, and black phosphorus (BP). The AMQDs-based PTAs also exhibited a unique feature of NIR-induced rapid degradability. Through both in vitro and in vivo studies, the PEG-coated AMQDs demonstrated notable NIR-induced tumor ablation ability. This work is expected to expand the utility of 2D antimonene (AM) to biomedical applications through the development of an entirely novel PTA platform.
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100Guo, T.; Tang, Q.; Guo, Y.; Qiu, H.; Dai, J.; Xing, C.; Zhuang, S.; Huang, G. Boron Quantum Dots for Photoacoustic Imaging-Guided Photothermal Therapy. ACS Appl. Mater. Interfaces 2021, 13 (1), 306– 311, DOI: 10.1021/acsami.0c21198Google Scholar100https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtVyjuw%253D%253D&md5=30d8cda970e60c6d13add1fe507e3c3cBoron Quantum Dots for Photoacoustic Imaging-Guided Photothermal TherapyGuo, Tao; Tang, Qiuyu; Guo, Yating; Qiu, Honglong; Dai, Jing; Xing, Chao; Zhuang, Shihao; Huang, GuomingACS Applied Materials & Interfaces (2021), 13 (1), 306-311CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Photothermal therapy is a new type of tumor therapy with great potential. An ideal photothermal therapy agent should have high photothermal conversion effect, low biol. toxicity, and degradability. The development of novel photothermal therapy agents with these properties is of great demand. In this study, we synthesized boron quantum dots (BQDs) with an ultrasmall hydrodynamic diam. Both in vitro and in vivo studies show that the as-synthesized BQDs have good biol. safety, high photoacoustic imaging performance, and photothermal conversion ability, which can be used for photoacoustic imaging-guided photothermal agents for tumor treatment. Our investigations confirm that the BQDs hold great promise in tumor theranostic applications.
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101Srivastava, S. B.; Melikov, R.; Yildiz, E.; Han, M.; Sahin, A.; Nizamoglu, S. Efficient Photocapacitors via Ternary Hybrid Photovoltaic Optimization for Photostimulation of Neurons. Biomed. Opt. Express 2020, 11 (9), 5237, DOI: 10.1364/BOE.396068Google Scholar101https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXisFSrs7rI&md5=62a8d66d6b8798f5cca61e5d189b36b7Efficient photocapacitors via ternary hybrid photovoltaic optimization for photostimulation of neuronsSrivastava, Shashi Bhushan; Melikov, Rustamzhon; Yildiz, Erdost; Han, Mertcan; Sahin, Afsun; Nizamoglu, SedatBiomedical Optics Express (2020), 11 (9), 5237-5248CODEN: BOEICL; ISSN:2156-7085. (Optical Society of America)Optoelectronic photoelectrodes based on capacitive charge-transfer offer an attractive route to develop safe and effective neuromodulators. Here, we demonstrate efficient optoelectronic photoelectrodes that are based on the incorporation of quantum dots (QDs) into poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-Phenyl-C61-butyric acid Me ester (PCBM) bulk heterojunction. We control the performance of the photoelectrode by the blend ratio, thickness, and nanomorphol. of the ternary bulk heterojunction. The optimization led to a photocapacitor that has a photovoltage of 450 mV under a light intensity level of 20 mW.cm-2 and a responsivity of 99 mA/W corresponding to the most light-sensitive org. photoelectrode reported to date. The photocapacitor can facilitate action potential generation by hippocampal neurons via burst waveforms at an intensity level of 20 mW.cm-2. Therefore, the results point to an alternative direction in the engineering of safe and ultra-light-sensitive neural interfaces.
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102Han, M.; Bahmani Jalali, H.; Yildiz, E.; Qureshi, M. H.; Şahin, A.; Nizamoglu, S. Photovoltaic Neurointerface Based on Aluminum Antimonide Nanocrystals. Commun. Mater. 2021, 2 (1), 19, DOI: 10.1038/s43246-021-00123-4Google Scholar102https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XotVCktr4%253D&md5=cf9de0001d958294430f880cd1a090f5Photovoltaic neurointerface based on aluminum antimonide nanocrystalsHan, Mertcan; Bahmani Jalali, Houman; Yildiz, Erdost; Qureshi, Mohammad Haroon; Sahin, Afsun; Nizamoglu, SedatCommunications Materials (2021), 2 (1), 19CODEN: CMOAGE; ISSN:2662-4443. (Nature Portfolio)Light activated modulation of neural activity is an emerging field for the basic investigation of neural systems and development of new therapeutic methods such as artificial retina. Colloidal inorg. nanocrystals have great potential for neural interfaces due to their adjustable optoelectronic properties via high-level structural, compositional, and size control. However, toxic heavy metal content (e.g., cadmium, mercury), electrochem. coupling to the cells and low photon-to-current efficiency limit their effective use. Here, we introduce the use of aluminum antimonide (AlSb) nanocrystals as the cell interfacing layer for capacitive neural stimulation in the blue spectrum. We demonstrate successful photostimulation of primary hippocampal neurons below ocular safety limits. In addn., our device shows high biocompatibility in vitro and passive accelerated ageing tests indicate a functional lifetime over 3 years showing their feasible use for chronic implants. We demonstrate that nanocrystal biointerfaces hold high promise for future bioelectronics and protheses.
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103Keuleyan, S.; Kohler, J.; Guyot-Sionnest, P. Photoluminescence of Mid-Infrared HgTe Colloidal Quantum Dots. J. Phys. Chem. C 2014, 118 (5), 2749– 2753, DOI: 10.1021/jp409061gGoogle Scholar103https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXnsV2ntg%253D%253D&md5=39eca69f0eff7c324b44e1546897884aPhotoluminescence of Mid-Infrared HgTe Colloidal Quantum DotsKeuleyan, Sean; Kohler, John; Guyot-Sionnest, PhilippeJournal of Physical Chemistry C (2014), 118 (5), 2749-2753CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The photoluminescence quantum yield of HgTe colloidal quantum dots is measured from 1800 to 6500 cm-1. There is a steep drop to low energy reminiscent of the generic gap law. However, direct evidence of energy transfer to the C-H stretch and overtone vibrations is apparent when temp. tunes the PL wavelength of a given sample through the vibrational resonances. Calcns. based on the radiative rate and resonant energy transfer to the ligand vibrations appear to account for much of the quantum yield drop. Power-dependent photoluminescence lifetime measurements on 3.7 nm particles show fast, ∼50 ps, biexciton lifetime similar to other colloidal quantum dot systems of similar sizes.
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104Keuleyan, S. E.; Guyot-Sionnest, P.; Delerue, C.; Allan, G. Mercury Telluride Colloidal Quantum Dots: Electronic Structure, Size-Dependent Spectra, and Photocurrent Detection up to 12 Μm. ACS Nano 2014, 8 (8), 8676– 8682, DOI: 10.1021/nn503805hGoogle Scholar104https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtleqt7jP&md5=4fbdd230d199457c5e20899dffd26347Mercury Telluride Colloidal Quantum Dots: Electronic Structure, Size-Dependent Spectra, and Photocurrent Detection up to 12 μmKeuleyan, Sean E.; Guyot-Sionnest, Philippe; Delerue, Christophe; Allan, GuyACS Nano (2014), 8 (8), 8676-8682CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)HgTe colloidal quantum dots are synthesized with high monodispersivity with sizes up to ∼15 nm corresponding to a room temp. absorption edge at ∼5 μm. The shape is tetrahedral for larger sizes and up to five peaks are seen in the absorption spectra with a clear size dependence. The size range of the HgTe quantum dots is extended to ∼20 nm using regrowth. The corresponding room temp. photoluminescence and absorption edge reach into the long-wave IR, past 8 μm. Upon cooling to liq. nitrogen temp., a photoconductive response is obtained in the long-wave IR region up to 12 μm. Configuration-interaction tight-binding calcns. successfully explain the spectra and the size dependence. The five optical features can be assigned to sets of single hole to single electron transitions whose strengths are strongly influenced by the multiband/multiorbital character of the quantum-dot electronic states.
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105Keuleyan, S.; Lhuillier, E.; Brajuskovic, V.; Guyot-Sionnest, P. Mid-Infrared HgTe Colloidal Quantum Dot Photodetectors. Nat. Photonics 2011, 5 (8), 489– 493, DOI: 10.1038/nphoton.2011.142Google Scholar105https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpsFWmtLc%253D&md5=3de241869a3f34c4770970ccfaa3e30bMid-infrared HgTe colloidal quantum dot photodetectorsKeuleyan, Sean; Lhuillier, Emmanuel; Brajuskovic, Vuk; Guyot-Sionnest, PhilippeNature Photonics (2011), 5 (8), 489-493CODEN: NPAHBY; ISSN:1749-4885. (Nature Publishing Group)Today's IR imaging devices are based on bulk and quantum-confined epitaxial materials and would benefit greatly from higher operating temps. and lower cost. Imaging chips based on colloidal quantum dot technol. could offer a convenient lower-cost alternative, but, to date, the spectral range of operation of colloidal quantum dots has been limited. In this Letter, we report colloidal HgTe quantum dot photodetectors with a room-temp. photoresponse beyond 5 μm, the longest interband absorption wavelength reported so far for colloidal materials. The photodetectors are fabricated from colloidal solns., which are then drop-cast as thin films on electrodes. Operation covering the important atm. mid-wavelength IR transparency window between 3 and 5 μm is demonstrated.
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106Åkerman, M. E.; Chan, W. C. W.; Laakkonen, P.; Bhatia, S. N.; Ruoslahti, E. Nanocrystal Targeting in Vivo. Proc. Natl. Acad. Sci. U. S. A. 2002, 99 (20), 12617– 12621, DOI: 10.1073/pnas.152463399Google Scholar106https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XnvFGiu7c%253D&md5=6acdbfb5997f6cd27c27db63d1f2ba79Nanocrystal targeting in vivoAkerman, Maria E.; Chan, Warren C. W.; Laakkonen, Pirjo; Bhatia, Sangeeta N.; Ruoslahti, ErkkiProceedings of the National Academy of Sciences of the United States of America (2002), 99 (20), 12617-12621CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Inorg. nanostructures that interface with biol. systems have recently attracted widespread interest in biol. and medicine. Nanoparticles are thought to have potential as novel intravascular probes for both diagnostic (e.g., imaging) and therapeutic purposes (e.g., drug delivery). Crit. issues for successful nanoparticle delivery include the ability to target specific tissues and cell types and escape from the biol. particulate filter known as the reticuloendothelial system. We set out to explore the feasibility of in vivo targeting by using semiconductor quantum dots (qdots). Qdots are small (<10 nm) inorg. nanocrystals that possess unique luminescent properties; their fluorescence emission is stable and tuned by varying the particle size or compn. We show that ZnS-capped CdSe qdots coated with a lung-targeting peptide accumulate in the lungs of mice after i.v. injection, whereas two other peptides specifically direct qdots to blood vessels or lymphatic vessels in tumors. We also show that adding polyethylene glycol to the qdot coating prevents nonselective accumulation of qdots in reticuloendothelial tissues. These results encourage the construction of more complex nanostructures with capabilities such as disease sensing and drug delivery.
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107Larson, D. R.; Zipfel, W. R.; Williams, R. M.; Clark, S. W.; Bruchez, M. P.; Wise, F. W.; Webb, W. W. Water-Soluble Quantum Dots for Multiphoton Fluorescence Imaging in Vivo. Science (80-.). 2003, 300 (5624), 1434– 1436, DOI: 10.1126/science.1083780Google Scholar107https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXktFGktLc%253D&md5=a8ac89b0ae3234ec3d9f121a18d0adc5Water-soluble quantum dots for multiphoton fluorescence imaging in vivoLarson, Daniel R.; Zipfel, Warren R.; Williams, Rebecca M.; Clark, Stephen W.; Bruchez, Marcel P.; Wise, Frank W.; Webb, Watt W.Science (Washington, DC, United States) (2003), 300 (5624), 1434-1437CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)The use of semiconductor nanocrystals (quantum dots) as fluorescent labels for multiphoton microscopy enables multicolor imaging in demanding biol. environments such as living tissue. We characterized water-sol. cadmium selenide-zinc sulfide quantum dots for multiphoton imaging in live animals. These fluorescent probes have two-photon action cross sections as high as 47,000 Goeppert-Mayer units, by far the largest of any label used in multiphoton microscopy. We visualized quantum dots dynamically through the skin of living mice, in capillaries hundreds of micrometers deep. We found no evidence of blinking (fluorescence intermittency) in soln. on nanosecond to millisecond time scales.
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108Chan, W. C. W.; Nie, S. Quantum Dot Bioconjugates for Ultrasensitive Nonisotopic Detection. Science (80-.). 1998, 281 (5385), 2016– 2018, DOI: 10.1126/science.281.5385.2016Google Scholar108https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtlKnsrk%253D&md5=481c7a81438f03ca6c871d30afde6eb3Quantum dot bioconjugates for ultrasensitive nonisotopic detectionChan, Warren C. W.; Nile, ShumingScience (Washington, D. C.) (1998), 281 (5385), 2016-2018CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomols. for use in ultra-sensitive biol. detection. In comparison with org. dyes such as rhodamine, this class of luminescent labels is 20 times as bright, 100 times as stable against photobleaching, and one-third as wide in spectral linewidth. These nanometer-sized conjugates are water-sol. and biocompatible. Quantum dots that were labeled with the protein transferrin underwent receptor-mediated endocytosis in cultured HeLa cells, and those dots that were labeled with immunomols. recognized specific antibodies or antigens.
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109Parak, W. J.; Boudreau, R.; Le Gros, M.; Gerion, D.; Zanchet, D.; Micheel, C. M.; Williams, S. C.; Alivisatos, A. P.; Larabell, C. Cell Motility and Metastatic Potential Studies Based on Quantum Dot Imaging of Phagokinetic Tracks. Adv. Mater. 2002, 14 (12), 882– 885, DOI: 10.1002/1521-4095(20020618)14:12<882::AID-ADMA882>3.0.CO;2-YGoogle Scholar109https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XltlGju7o%253D&md5=65b603bb72df34185d70a44d5bd189abCell motility and metastatic potential studies based on quantum dot imaging of phagokinetic tracksParak, Wolfgang J.; Boudreau, Rosanne; Le Gros, Mark; Gerion, Daniele; Zanchet, Daniela; Micheel, Christine M.; Williams, Shara C.; Alivisatos, A. Paul; Larabell, CarolynAdvanced Materials (Weinheim, Germany) (2002), 14 (12), 882-885CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH)The recent advances in semiconductor nanotechnol. have aided in the improvement of cell motility assays, particularly in the phagokinetic uptake of colloidal quantum dots. Thin layers of colloidal semiconductor nanocrystals were deposited on collagen-coated tissue culture substrates, followed by seeding of cells. Two types of cell lines were examd. in detail, human mammary epithelial tumor cells and non-tumor cells. The colloidal quantum dots were readily ingested by all of the cell lines examd. The degree of the nanocrystal uptake reflects the migratory behavior of the cell via a process of pino-, endo- and/or phagocytosis of the surrounding matrix. The nanocrystals readily adhere to the cell surface, most likely due to interactions of the cell surface glycoproteins and glycolipids with the nanocrystal surface. The colloidal quantum-dot based phagonkinetic tracking proved to be a versatile and powerful method of quantifying motility in a wide variety of circumstances.
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110Wu, X.; Liu, H.; Liu, J.; Haley, K. N.; Treadway, J. A.; Larson, J. P.; Ge, N.; Peale, F.; Bruchez, M. P. Immunofluorescent Labeling of Cancer Marker Her2 and Other Cellular Targets with Semiconductor Quantum Dots. Nat. Biotechnol. 2003, 21 (1), 41– 46, DOI: 10.1038/nbt764Google Scholar110https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhvVyl&md5=66f13dafe63f510984d5b953c59266fbImmunofluorescent labeling of cancer marker Her2 and other cellular targets with semiconductor quantum dotsWu, Xingyong; Liu, Hongjian; Liu, Jianquan; Haley, Kari N.; Treadway, Joseph A.; Larson, J. Peter; Ge, Nianfeng; Peale, Frank; Bruchez, Marcel P.Nature Biotechnology (2003), 21 (1), 41-46CODEN: NABIF9; ISSN:1087-0156. (Nature Publishing Group)Semiconductor quantum dots (QDs) are among the most promising emerging fluorescent labels for cellular imaging. However, it is unclear whether QDs, which are nanoparticles rather than small mols., can specifically and effectively label mol. targets at a subcellular level. Here we have used QDs linked to IgG (IgG) and streptavidin to label the breast cancer marker Her2 on the surface of fixed and live cancer cells, to stain actin and microtubule fibers in the cytoplasm, and to detect nuclear antigens inside the nucleus. All labeling signals are specific for the intended targets and are brighter and considerably more photostable than comparable org. dyes. Using QDs with different emission spectra conjugated to IgG and streptavidin, we simultaneously detected two cellular targets with one excitation wavelength. The results indicate that QD-based probes can be very effective in cellular imaging and offer substantial advantages over org. dyes in multiplex target detection.
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111Dahan, M.; Lévi, S.; Luccardini, C.; Rostaing, P.; Riveau, B.; Triller, A. Diffusion Dynamics of Glycine Receptors Revealed by Single-Quantum Dot Tracking. Science (80-.). 2003, 302 (5644), 442– 445, DOI: 10.1126/science.1088525Google ScholarThere is no corresponding record for this reference.
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112Prevarskaya, N.; Skryma, R.; Bidaux, G.; Flourakis, M.; Shuba, Y. Ion Channels in Death and Differentiation of Prostate Cancer Cells. Cell Death Differ. 2007, 14 (7), 1295– 1304, DOI: 10.1038/sj.cdd.4402162Google Scholar112https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXms1Sqs7s%253D&md5=c15ce1972a630efb9b8fd83837c5e8d4Ion channels in death and differentiation of prostate cancer cellsPrevarskaya, N.; Skryma, R.; Bidaux, G.; Flourakis, M.; Shuba, Y.Cell Death and Differentiation (2007), 14 (7), 1295-1304CODEN: CDDIEK; ISSN:1350-9047. (Nature Publishing Group)A review. Plasma membrane ion channels contribute to virtually all basic cellular processes, including such crucial ones for maintaining tissue homeostasis as proliferation, differentiation, and apoptosis. Enhanced proliferation, aberrant differentiation, and impaired ability to die are the prime reasons for abnormal tissue growth, which can eventually turn into uncontrolled expansion and invasion, characteristic of cancer. Prostate cancer (PCa) cells express a variety of plasma membrane ion channels. By providing the influx of essential signaling ions, perturbing intracellular ion concns., regulating cell vol., and maintaining membrane potential, PCa cells are critically involved in proliferation, differentiation, and apoptosis. PCa cells of varying metastatic ability can be distinguished by their ion channel characteristics. Increased malignancy and invasiveness of androgen-independent PCa cells is generally assocd. with the shift to a 'more excitable' phenotype of their plasma membrane. This shift is manifested by the appearance of voltage-gated Na+ and Ca2+ channels which contribute to their enhanced apoptotic resistance together with down regulated store-operated Ca2+ influx, altered expression of different K+ channels and members of the Transient Receptor Potential (TRP) channel family, and strengthened capability for maintaining vol. constancy. The present review examines channel types expressed by PCa cells and their involvement in metastatic behaviors.
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113Bareket, L.; Waiskopf, N.; Rand, D.; Lubin, G.; David-Pur, M.; Ben-Dov, J.; Roy, S.; Eleftheriou, C.; Sernagor, E.; Cheshnovsky, O.; Banin, U.; Hanein, Y. Semiconductor Nanorod-Carbon Nanotube Biomimetic Films for Wire-Free Photostimulation of Blind Retinas. Nano Lett. 2014, 14 (11), 6685– 6692, DOI: 10.1021/nl5034304Google Scholar113https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVegu7vN&md5=45b99d5d55ba75e8878f5a4b66bb0224Semiconductor Nanorod-Carbon Nanotube Biomimetic Films for Wire-Free Photostimulation of Blind RetinasBareket, Lilach; Waiskopf, Nir; Rand, David; Lubin, Gur; David-Pur, Moshe; Ben-Dov, Jacob; Roy, Soumyendu; Eleftheriou, Cyril; Sernagor, Evelyne; Cheshnovsky, Ori; Banin, Uri; Hanein, YaelNano Letters (2014), 14 (11), 6685-6692CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)We report the development of a semiconductor nanorod-carbon nanotube based platform for wire-free, light induced retina stimulation. A plasma polymd. acrylic acid midlayer was used to achieve covalent conjugation of semiconductor nanorods directly onto neuro-adhesive, three-dimensional carbon nanotube surfaces. Photocurrent, photovoltage, and fluorescence lifetime measurements validate efficient charge transfer between the nanorods and the carbon nanotube films. Successful stimulation of a light-insensitive chick retina suggests the potential use of this novel platform in future artificial retina applications.
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114Gabay, T.; Ben-David, M.; Kalifa, I.; Sorkin, R.; Abrams, Z. R.; Ben-Jacob, E.; Hanein, Y. Electro-Chemical and Biological Properties of Carbon Nanotube Based Multi-Electrode Arrays. Nanotechnology 2007, 18 (3), 035201, DOI: 10.1088/0957-4484/18/3/035201Google Scholar114https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXjtFChsb8%253D&md5=996cd678dae95af94ab505c704b9d1e3Electro-chemical and biological properties of carbon nanotube based multi-electrode arraysGabay, Tamir; Ben-David, Moti; Kalifa, Itshak; Sorkin, Raya; Abrams, Ze'ev R.; Ben-Jacob, Eshel; Hanein, YaelNanotechnology (2007), 18 (3), 035201/1-035201/6CODEN: NNOTER; ISSN:0957-4484. (Institute of Physics Publishing)A novel class of micro-electrodes was fabricated by synthesizing high d. carbon nanotube islands on lithog. defined, passivated titanium nitride conductors on a silicon dioxide substrate. Electrochem. characterization in phosphate buffered saline of these new electrodes reveals superb electrochem. properties marked by featureless rectangular cyclic voltammetry curves corresponding to a DC surface specific capacitance and a vol. specific capacitance as high as 10 mF cm-2 and 10 F cm-3, resp. These electrodes are also characterized by a slowly varying impedance magnitude over the range of 1 Hz to 20 kHz. High fidelity extracellular recordings from cultured neurons were performed and analyzed to validate the effectiveness of the fabricated electrodes. The enhanced electrochem. properties of the electrodes, their flexible and simple micro-fabrication prepn. procedure as well as their bio-compatibility and durability suggest that carbon nanotube electrodes are a promising platform for high resoln. capacitive electrochem. applications.
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115Shoval, A.; Adams, C.; David-Pur, M.; Shein, M.; Hanein, Y.; Sernagor, E. Carbon Nanotube Electrodes for Effective Interfacing with Retinal Tissue. Front. Neuroeng. 2009, 2 (APR), 4, DOI: 10.3389/neuro.16.004.2009Google Scholar115https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXptlGitr4%253D&md5=2b0c23f595c16561b755535fd39e9589Carbon nanotube electrodes for effective interfacing with retinal tissueShoval, Asaf; Adams, Christopher; David-Pur, Moshe; Shein, Mark; Hanein, Yael; Sernagor, EvelyneFrontiers in Neuroengineering (2009), 2 (April), 4CODEN: FNREIF; ISSN:1662-6443. (Frontiers Research Foundation)We have investigated the use of carbon nanotube coated microelectrodes as an interface material for retinal recording and stimulation applications. Test devices were micro-fabricated and consisted of 60, 30 μm diam. electrodes at spacing of 200 μm. These electrodes were coated via chem. vapor deposition of carbon nanotubes, resulting in conducting, three dimensional surfaces with a high interfacial area. These attributes are important both for the quality of the cell-surface coupling as well as for electro-chem. interfacing efficiency. The entire chip was packaged to fit a com. multielectrode recording and stimulation system. Elec. recordings of spontaneous spikes from whole-mount neonatal mouse retinas were consistently obtained minutes after retinas were placed over the electrodes, exhibiting typical bursting and propagating waves. Most importantly, the signals obtained with carbon nanotube electrodes have exceptionally high signal to noise ratio, reaching values as high as 75. Moreover, spikes are marked by a conspicuous gradual increase in amplitude recorded over a period of minutes to hours, suggesting improvement in cell-electrode coupling. This phenomenon is not obsd. in conventional com. electrodes. Elec. stimulation using carbon nanotube electrodes was also achieved. We attribute the superior performances of the carbon nanotube electrodes to their three dimensional nature and the strong neuro-carbon nanotube affinity. The results presented here show the great potential of carbon nanotube electrodes for retinal interfacing applications. Specifically, our results demonstrate a route to achieve a redn. of the electrode down to few micrometers in order to achieve high efficacy local stimulation needed in retinal prosthetic devices.
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116Wong, W. T.; Sanes, J. R.; Wong, R. O. L. Developmentally Regulated Spontaneous Activity in the Embryonic Chick Retina. J. Neurosci. 1998, 18 (21), 8839– 8852, DOI: 10.1523/JNEUROSCI.18-21-08839.1998Google Scholar116https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntFOlu7w%253D&md5=36f824e5b14d985343c21dd82e869c54Developmentally regulated spontaneous activity in the embryonic chick retinaWong, Wai T.; Sanes, Joshua R.; Wong, Rachel O. L.Journal of Neuroscience (1998), 18 (21), 8839-8852CODEN: JNRSDS; ISSN:0270-6474. (Society for Neuroscience)Even before birth and the onset of sensory experience, neural activity plays an important role in shaping the vertebrate nervous system. In the embryonic chick visual system, activity in the retina before vision has been implicated in the refinement of retinotopic maps, the elimination of transient projections, and the survival of a full complement of neurons. In this study, the authors report the detection of a physiol. substrate for these phenomena: waves of spontaneous activity in the ganglion cell layer of the embryonic chick retina. The activity is robust and highly patterned, taking the form of large amplitude, rhythmic, and wide-ranging waves of excitation that propagate across the retina. Activity waves are most prominent and organized between embryonic days 13-18, coinciding with the developmental period during which retinal axons refine their connections in their targets. The spatial and temporal features of the patterns obsd. are consistent with the role of activity patterns in shaping eye-specific projections and retinotopic maps but inconsistent with the hypothesis that they specify lamina-specific projections in the tectum. Antagonists of glutamatergic and glycinergic transmission and of gap junctional communication suppress spontaneous activity, whereas antagonists to GABAergic transmission potentiate it. Based on these results, the authors propose that spontaneous activity in the ganglion cells is regulated by chem. inputs from both bipolar and amacrine cells and by gap junctional coupling involving ganglion cells.
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117Delori, F. C.; Webb, R. H.; Sliney, D. H. Maximum Permissible Exposures for Ocular Safety (ANSI 2000), with Emphasis on Ophthalmic Devices. J. Opt. Soc. Am. A 2007, 24 (5), 1250, DOI: 10.1364/JOSAA.24.001250Google Scholar117https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD2s3itVGgsg%253D%253D&md5=399ddf15e62e762ac178ce6c2bea4b73Maximum permissible exposures for ocular safety (ANSI 2000), with emphasis on ophthalmic devicesDelori Francois C; Webb Robert H; Sliney David HJournal of the Optical Society of America. A, Optics, image science, and vision (2007), 24 (5), 1250-65 ISSN:1084-7529.After discussing the rationale and assumptions of the ANSI Z136.1-2000 Standard for protection of the human eye from laser exposure, we present the concise formulation of the exposure limits expressed as maximum permissible radiant exposure (in J/cm(2)) for light overfilling the pupil. We then translate the Standard to a form that is more practical for typical ophthalmic devices or in vision research situations, implementing the special qualifications of the Standard. The safety limits are then expressed as radiant power (watts) entering the pupil of the eye. Exposure by repetitive pulses is also addressed, as this is frequently employed in ophthalmic applications. Examples are given that will familiarize potential users with this format.
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118Yan, B.; Vakulenko, M.; Min, S. H.; Hauswirth, W. W.; Nirenberg, S. Maintaining Ocular Safety with Light Exposure, Focusing on Devices for Optogenetic Stimulation. Vision Res. 2016, 121, 57– 71, DOI: 10.1016/j.visres.2016.01.006Google Scholar118https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28jhtlSjsg%253D%253D&md5=17713785b62a0a0cd287d4a82aad4bfaMaintaining ocular safety with light exposure, focusing on devices for optogenetic stimulationYan Boyuan; Vakulenko Maksim; Min Seok-Hong; Hauswirth William W; Nirenberg SheilaVision research (2016), 121 (), 57-71 ISSN:.Optogenetics methods are rapidly being developed as therapeutic tools for treating neurological diseases, in particular, retinal degenerative diseases. A critical component of the development is testing the safety of the light stimulation used to activate the optogenetic proteins. While the stimulation needs to be sufficient to produce neural responses in the targeted retinal cell class, it also needs to be below photochemical and photothermal limits known to cause ocular damage. The maximal permissible exposure is determined by a variety of factors, including wavelength, exposure duration, visual angle, pupil size, pulse width, pulse pattern, and repetition frequency. In this paper, we develop utilities to systematically and efficiently assess the contributions of these parameters in relation to the limits, following directly from the 2014 American National Standards Institute (ANSI). We also provide an array of stimulus protocols that fall within the bounds of both safety and effectiveness. Additional verification of safety is provided with a case study in rats using one of these protocols.
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119Tamang, S.; Lincheneau, C.; Hermans, Y.; Jeong, S.; Reiss, P. Chemistry of InP Nanocrystal Syntheses. Chem. Mater. 2016, 28 (8), 2491– 2506, DOI: 10.1021/acs.chemmater.5b05044Google Scholar119https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XltFGnt7g%253D&md5=66b19e4be3d991d6612163e82596497aChemistry of InP Nanocrystal SynthesesTamang, Sudarsan; Lincheneau, Christophe; Hermans, Yannick; Jeong, Sohee; Reiss, PeterChemistry of Materials (2016), 28 (8), 2491-2506CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)A review. Chem. synthesized InP nanocrystals (NCs) are drawing a large interest as a potentially less toxic alternative to CdSe-based nanocrystals. With a bulk band gap of 1.35 eV and an exciton Bohr radius of ∼10 nm the emission wavelength of InP NCs can in principle be tuned throughout the whole visible and near-IR range by changing their size. A few works reported fluorescence quantum yields exceeding 70% after overcoating the core NCs with appropriate shell materials. Therefore, InP NCs are very promising for use in lighting and display applications. However, a no. of challenges remain to be addressed to progress from isolated research results to robust and reproducible synthesis methods for high quality InP NCs. First of all, the size distribution of the as-synthesized NCs needs to be reduced, which directly translates into more narrow emission line widths. Next, reliable protocols are required for achieving a given emission wavelength at high reaction yield and for further improving the emission efficiency and chem. and photostability. Advances in these directions were hampered for a long time by the specific properties of InP, such as the rather covalent nature of binding implying harsh synthesis conditions, high sensitivity toward oxidn., and limited choice of P precursors. However, in recent years a much better understanding of the precursor conversion kinetics and reaction mechanisms was achieved, giving this field new impulse. A comprehensive overview from initial synthetic approaches to the most recent developments is provided. First, the authors highlight the fundamental differences in the syntheses of InP-based NCs with respect to established II-VI and IV-VI semiconductor NCs comparing their nucleation and growth stages. Next, the authors inspect in detail the influence of the nature of the P and In precursors used and of reaction additives, such as Zn carboxylates or alkylamines, on the properties of the NCs. Finally, core/shell systems and doped InP NCs are discussed, and perspectives in this field are given.
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120Sargent, E. H. Colloidal Quantum Dot Solar Cells. Nat. Photonics 2012, 6 (3), 133– 135, DOI: 10.1038/nphoton.2012.33Google Scholar120https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XivV2ns7g%253D&md5=0e8f4729ee05fab745965fa0e1271059Colloidal quantum dot solar cellsSargent, Edward H.Nature Photonics (2012), 6 (3), 133-135CODEN: NPAHBY; ISSN:1749-4885. (Nature Publishing Group)A review. Solar cells based on soln.-processed semiconductor nanoparticles - colloidal quantum dots - have seen rapid advances in recent years. By offering full-spectrum solar harvesting, these cells are poised to address the urgent need for low-cost, high-efficiency photovoltaics.
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121Li, W.; Zhong, X. Capping Ligand-Induced Self-Assembly for Quantum Dot Sensitized Solar Cells. J. Phys. Chem. Lett. 2015, 6 (5), 796– 806, DOI: 10.1021/acs.jpclett.5b00001Google Scholar121https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXisF2isbY%253D&md5=d40c0968362f3f3f9a05c4b88b260728Capping Ligand-Induced Self-Assembly for Quantum Dot Sensitized Solar CellsLi, Wenjie; Zhong, XinhuaJournal of Physical Chemistry Letters (2015), 6 (5), 796-806CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)A review. Quantum dot-sensitized solar cells (QDSCs), having the advantages of low-cost assembling process, economically viable materials and intrinsic optoelectronic properties of QD sensitizers, are regarded as attractive candidates for the third-generation solar cells. In spite of the previous unsatisfied performance resulted from poor sensitization, an increasing power conversion efficiency has been exptl. confirmed with the development of effective deposition approaches in the last five years. In this perspective article, an overview is presented on versatile QD deposition methods, regarding mainly the effective loading of QDs and surface chem. issues. Linker-assisted assembly, a most efficient sensitizer deposition approach to achieve fast, uniform and dense coverage of the sensitizers on mesoporous TiO2 film electrode, is discussed with emphasis. Recent advances based on this deposition technique in achieving high efficiency are presented. Also, combined efforts regarding the overall improvement of the device have been discussed to provide more possible access to higher power conversion efficiencies of the QDSCs.
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122Yang, S.; Zhao, P.; Zhao, X.; Qu, L.; Lai, X. InP and Sn:InP Based Quantum Dot Sensitized Solar Cells. J. Mater. Chem. A 2015, 3 (43), 21922– 21929, DOI: 10.1039/C5TA04925CGoogle Scholar122https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsFWhtLzN&md5=175f194318bd7e347e6b8d9f76fe1ef9InP and Sn:InP based quantum dot sensitized solar cellsYang, Suolong; Zhao, Pengxiang; Zhao, Xiaochong; Qu, Liangti; Lai, XinchunJournal of Materials Chemistry A: Materials for Energy and Sustainability (2015), 3 (43), 21922-21929CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)Due to the ideal band gap and environmental friendliness, InP is a promising light-harvesting material in photovoltaic cells. However, green InP based quantum dot sensitized solar cells (QDSSCs) have been rarely reported. Herein, nearly monodispersed Sn doped InP (Sn:InP) quantum dots (QDs) were synthesized by the 1-pot nucleation doping method, and used as the sensitizer in the construction of QDSSCs. High QD loadings on the TiO2 film electrodes were achieved by using the capping ligand-induced self-assembly (CLIS) sensitization technique. The resulting champion Sn:InP cell shows a power conversion efficiency (PCE) of 3.54% under AM 1.5 G (simulated 1 sun illumination), which is remarkably higher than that of un-doped InP QD based ones. This improvement is ascribed to the regulation role of the band gap by Sn dopant in the InP QDs. The Sn:InP QDSSCs exhibit moderate efficiency, good reproducibility and stability. These new findings may pave the way for the performance improvements of other QD photovoltaic devices.
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123Yang, Z.; Chen, C. Y.; Roy, P.; Chang, H. T. Quantum Dot-Sensitized Solar Cells Incorporating Nanomaterials. Chem. Commun. 2011, 47 (34), 9561– 9571, DOI: 10.1039/c1cc11317hGoogle Scholar123https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVWgs7zF&md5=3580778444a1677fe892d14b6af25aa7Quantum dot-sensitized solar cells incorporating nanomaterialsYang, Zusing; Chen, Chia-Ying; Roy, Prathik; Chang, Huan-TsungChemical Communications (Cambridge, United Kingdom) (2011), 47 (34), 9561-9571CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Quantum dot-sensitized solar cells (QDSSCs) are interesting energy devices because of their (i) impressive ability to harvest sunlight and generate multiple electron/hole pairs, (ii) ease of fabrication, and (iii) low cost. The power conversion efficiencies (η) of most QDSSCs (typically < 4%) are, however, less than those (up to 12%) of dye-sensitized solar cells, mainly because of narrow absorption ranges and charge recombination occurring at the QD-electrolyte and TiO2-electrolyte interfaces. To further increase the values of η of QDSSCs, it will be necessary to develop new types of working electrodes, sensitizers, counter electrodes, and electrolytes. This article describes the nanomaterials that were used recently as electronic conductors, sensitizers, and counter electrodes in QDSSCs. The nature, size, morphol., and quantity of these nanomaterials all play important roles affecting the efficiencies of electron injection and light harvesting. The behavior is discussed of several important types of semiconductor nanomaterials (sensitizers, including CdS, Ag2S, CdSe, CdTe, CdHgTe, InAs, and PbS) and nanomaterials (notably TiO2, ZnO, and carbon-based species) that were developed to improve the electron transport efficiency of QDSSCs. The prepn. is pointed out of new generations of nanomaterials for QDSSCs and the types of electrolytes, particularly iodide/triiodide electrolytes (I-/I3-), polysulfide electrolytes (S2-/Sx2-), and cobalt redox couples ([Co(o-phen)32+/3+]), that improve their lifetimes. With advances in nanotechnol., significant improvements are foreseen in the efficiency (η > 6%) and durability (> 3000 h) of QDSSCs.
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124Medintz, I. L.; Uyeda, H. T.; Goldman, E. R.; Mattoussi, H. Quantum Dot Bioconjugates for Imaging, Labelling and Sensing. Nat. Mater. 2005, 4 (6), 435– 446, DOI: 10.1038/nmat1390Google Scholar124https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXks1Cit7k%253D&md5=5a012c5b15547485aeea42f41d212b45Quantum dot bioconjugates for imaging, labelling and sensingMedintz, Igor L.; Uyeda, H. Tetsuo; Goldman, Ellen R.; Mattoussi, HediNature Materials (2005), 4 (6), 435-446CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)A review. One of the fastest moving and most exciting interfaces of nanotechnol. is the use of quantum dots (QDs) in biol. The unique optical properties of QDs make them appealing as in vivo and in vitro fluorophores in a variety of biol. investigations, in which traditional fluorescent labels based on org. mols. fall short of providing long-term stability and simultaneous detection of multiple signals. The ability to make QDs water sol. and target them to specific biomols. has led to promising applications in cellular labeling, deep-tissue imaging, assay labeling and as efficient fluorescence resonance energy transfer donors. Despite recent progress, much work still needs to be done to achieve reproducible and robust surface functionalization and develop flexible bioconjugation techniques. In this review, we look at current methods for prepg. QD bioconjugates as well as presenting an overview of applications. The potential of QDs in biol. has just begun to be realized and new avenues will arise as our ability to manipulate these materials improves.
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125Livache, C.; Martinez, B.; Goubet, N.; Gréboval, C.; Qu, J.; Chu, A.; Royer, S.; Ithurria, S.; Silly, M. G.; Dubertret, B.; Lhuillier, E. A Colloidal Quantum Dot Infrared Photodetector and Its Use for Intraband Detection. Nat. Commun. 2019, 10 (1), 2125, DOI: 10.1038/s41467-019-10170-8Google Scholar125https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3M7kt1WrsA%253D%253D&md5=85ad17dbd68b7eb6d9d145f5e040eed5A colloidal quantum dot infrared photodetector and its use for intraband detectionLivache Clement; Martinez Bertille; Goubet Nicolas; Greboval Charlie; Qu Junling; Chu Audrey; Royer Sebastien; Lhuillier Emmanuel; Livache Clement; Martinez Bertille; Goubet Nicolas; Ithurria Sandrine; Dubertret Benoit; Silly Mathieu GNature communications (2019), 10 (1), 2125 ISSN:.Wavefunction engineering using intraband transition is the most versatile strategy for the design of infrared devices. To date, this strategy is nevertheless limited to epitaxially grown semiconductors, which lead to prohibitive costs for many applications. Meanwhile, colloidal nanocrystals have gained a high level of maturity from a material perspective and now achieve a broad spectral tunability. Here, we demonstrate that the energy landscape of quantum well and quantum dot infrared photodetectors can be mimicked from a mixture of mercury selenide and mercury telluride nanocrystals. This metamaterial combines intraband absorption with enhanced transport properties (i.e. low dark current, fast time response and large thermal activation energy). We also integrate this material into a photodiode with the highest infrared detection performances reported for an intraband-based nanocrystal device. This work demonstrates that the concept of wavefunction engineering at the device scale can now be applied for the design of complex colloidal nanocrystal-based devices.
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126Meinardi, F.; McDaniel, H.; Carulli, F.; Colombo, A.; Velizhanin, K. A.; Makarov, N. S.; Simonutti, R.; Klimov, V. I.; Brovelli, S. Highly Efficient Large-Area Colourless Luminescent Solar Concentrators Using Heavy-Metal-Free Colloidal Quantum Dots. Nat. Nanotechnol. 2015, 10 (10), 878– 885, DOI: 10.1038/nnano.2015.178Google Scholar126https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlyls7vO&md5=b63662c4e01349d552589031b5cc71deHighly efficient large-area colorless luminescent solar concentrators using heavy-metal-free colloidal quantum dotsMeinardi, Francesco; McDaniel, Hunter; Carulli, Francesco; Colombo, Annalisa; Velizhanin, Kirill A.; Makarov, Nikolay S.; Simonutti, Roberto; Klimov, Victor I.; Brovelli, SergioNature Nanotechnology (2015), 10 (10), 878-885CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)Luminescent solar concentrators serving as semitransparent photovoltaic windows could become an important element in net zero energy consumption buildings of the future. Colloidal quantum dots are promising materials for luminescent solar concentrators as they can be engineered to provide the large Stokes shift necessary for suppressing reabsorption losses in large-area devices. Existing Stokes-shift-engineered quantum dots allow for only partial coverage of the solar spectrum, which limits their light-harvesting ability and leads to coloring of the luminescent solar concentrators, complicating their use in architecture. Here, we use quantum dots of ternary I-III-VI2 semiconductors to realize the first large-area quantum dot-luminescent solar concentrators free of toxic elements, with reduced reabsorption and extended coverage of the solar spectrum. By incorporating CuInSexS2-x quantum dots into photo-polymd. poly(lauryl methacrylate), we obtain freestanding, colorless slabs that introduce no distortion to perceived colors and are thus well suited for the realization of photovoltaic windows. Thanks to the suppressed reabsorption and high emission efficiencies of the quantum dots, we achieve an optical power efficiency of 3.2%. Ultrafast spectroscopy studies suggest that the Stokes-shifted emission involves a conduction-band electron and a hole residing in an intragap state assocd. with a native defect.
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127Sadeghi, S.; Bahmani Jalali, H.; Srivastava, S. B.; Melikov, R.; Baylam, I.; Sennaroglu, A.; Nizamoglu, S. High-Performance, Large-Area, and Ecofriendly Luminescent Solar Concentrators Using Copper-Doped InP Quantum Dots. iScience 2020, 23 (7), 101272, DOI: 10.1016/j.isci.2020.101272Google Scholar127https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtlWqtLrK&md5=7b50f8236f47e3addfe2e07750909c95High-Performance, Large-Area, and Ecofriendly Luminescent Solar Concentrators Using Copper-Doped InP Quantum DotsSadeghi, Sadra; Bahmani Jalali, Houman; Srivastava, Shashi Bhushan; Melikov, Rustamzhon; Baylam, Isinsu; Sennaroglu, Alphan; Nizamoglu, SedatiScience (2020), 23 (7), 101272CODEN: ISCICE; ISSN:2589-0042. (Elsevier B.V.)Colloidal quantum dots (QDs) are promising building blocks for luminescent solar concentrators (LSCs). For their widespread use, they need to simultaneously satisfy non-toxic material content, low reabsorption, high photoluminescence quantum yield, and large-scale prodn. Here, copper doping of zinc carboxylate-passivated InP core and nano-engineering of ZnSe shell facilitated high in-device quantum efficiency of QDs over 80%, having well-matched spectral emission profile with the photo-response of silicon solar cells. The optimized QD-LSCs showed an optical quantum efficiency of 37% and an internal concn. factor of 4.7 for a 10 x 10-cm2 device area under solar illumination, which is comparable with the state-of-the-art LSCs based on cadmium-contg. QDs and lead-contg. perovskites. Synthesis of the copper-doped InP/ZnSe QDs in gram-scale and large-area deposition (3,000 cm2) onto com. window glasses via doctor-blade technique showed their scalability for mass prodn. These results position InP-based QDs as a promising alternative for efficient solar energy harvesting.
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128Sadeghi, S.; Bahmani Jalali, H.; Melikov, R.; Ganesh Kumar, B.; Mohammadi Aria, M.; Ow-Yang, C. W.; Nizamoglu, S. Stokes-Shift-Engineered Indium Phosphide Quantum Dots for Efficient Luminescent Solar Concentrators. ACS Appl. Mater. Interfaces 2018, 10 (15), 12975– 12982, DOI: 10.1021/acsami.7b19144Google Scholar128https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXmt1Wksr0%253D&md5=df0a7a1b4b4f73e4b3a29e330ca7ba1eStokes-Shift-Engineered Indium Phosphide Quantum Dots for Efficient Luminescent Solar ConcentratorsSadeghi, Sadra; Bahmani Jalali, Houman; Melikov, Rustamzhon; Ganesh Kumar, Baskaran; Mohammadi Aria, Mohammad; Ow-Yang, Cleva W.; Nizamoglu, SedatACS Applied Materials & Interfaces (2018), 10 (15), 12975-12982CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Luminescent solar concentrators (LSCs) show promise because of their potential for low-cost, large-area, and high-efficiency energy harvesting. Stokes shift engineering of luminescent quantum dots (QDs) is a favorable approach to suppress reabsorption losses in LSCs; however, the use of highly toxic heavy metals in QDs constitutes a serious concern for environmental sustainability. Here, we report LSCs based on cadmium-free InP/ZnO core/shell QDs with type-II band alignment that allow for the suppression of reabsorption by Stokes shift engineering. The spectral emission and absorption overlap was controlled by the growth of a ZnO shell on an InP core. At the same time, the ZnO layer also facilitates the photostability of the QDs within the host matrix. We analyzed the optical performance of indium-based LSCs and identified the optical efficiency as 1.45%. The transparency, flexibility, and cadmium-free content of the LSCs hold promise for solar window applications.
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129Bahmani Jalali, H.; Sadeghi, S.; Baylam, I.; Han, M.; Ow-Yang, C. W.; Sennaroglu, A.; Nizamoglu, S. Exciton Recycling via InP Quantum Dot Funnels for Luminescent Solar Concentrators. Nano Res. 2021, 14 (5), 1488– 1494, DOI: 10.1007/s12274-020-3207-9Google Scholar129https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtVKntr7J&md5=fd289da0f19bcf3879fb8e8eb9a7d87aExciton recycling via InP quantum dot funnels for luminescent solar concentratorsBahmani Jalali, Houman; Sadeghi, Sadra; Baylam, Isinsu; Han, Mertcan; Ow-Yang, Cleva W.; Sennaroglu, Alphan; Nizamoglu, SedatNano Research (2021), 14 (5), 1488-1494CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)Luminescent solar concentrators (LSC) absorb large-area solar radiation and guide down-converted emission to solar cells for electricity prodn. Quantum dots (QDs) have been widely engineered at device and quantum dot levels for LSCs. Here, we demonstrate cascaded energy transfer and exciton recycling at nanoassembly level for LSCs. The graded structure composed of different sized toxic-heavy-metal-free InP/ZnS core/shell QDs incorporated on copper doped InP QDs, facilitating exciton routing toward narrow band gap QDs at a high nonradiative energy transfer efficiency of 66%. At the final stage of non-radiative energy transfer, the photogenerated holes make ultrafast electronic transitions to copper-induced mid-gap states for radiative recombination in the near-IR. The exciton recycling facilitates a photoluminescence quantum yield increase of 34% and 61% in comparison with semi-graded and ungraded energy profiles, resp. Thanks to the suppressed reabsorption and enhanced photoluminescence quantum yield, the graded LSC achieved an optical quantum efficiency of 22.2%. Hence, engineering at nanoassembly level combined with nonradiative energy transfer and exciton funneling offer promise for efficient solar energy harvesting. [graphic not available: see fulltext].
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130Jang, E.; Kim, Y.; Won, Y.-H.; Jang, H.; Choi, S.-M. Environmentally Friendly InP-Based Quantum Dots for Efficient Wide Color Gamut Displays. ACS Energy Lett. 2020, 5 (4), 1316– 1327, DOI: 10.1021/acsenergylett.9b02851Google Scholar130https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXlt1Sjtb8%253D&md5=5793bd9310fbf4b814126b44ce6207a3Environmentally friendly InP-vased quantum dots for efficient wide color gamut displaysJang, Eunjoo; Kim, Yongwook; Won, Yu-Ho; Jang, Hyosook; Choi, Seon-MyeongACS Energy Letters (2020), 5 (4), 1316-1327CODEN: AELCCP; ISSN:2380-8195. (American Chemical Society)A review. Quantum dots (QD) are regarded as ideal light emitters for current and next-generation displays. Hence, there is an urgent need to produce environmentally friendly QDs that show high efficiency and better color purity. From this perspective, a strategy of tuning the wavelength and spectral width is discussed to optimize the brightness and color space agreement. The crit. parameters affecting photophys. properties, such as the uniformity of the InP QD core, the thickness and shape of the ZnSe shell, the electron/hole distribution, surface dangling defects, oxidative phase, and the stacking faults in the cryst. structure, are examd. In addn., quant. analyses are suggested to understand the nature of the ligands so that practical applications can be diversified. Recently, QD-LEDs using InP-based QDs with controlled shell structure showed potential for future commercialization. For further development, improvement in the stability via the control of inorg. and org. passivating structures is required.
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131Eren, G. O.; Sadeghi, S.; Bahmani Jalali, H.; Ritter, M.; Han, M.; Baylam, I.; Melikov, R.; Onal, A.; Oz, F.; Sahin, M.; Ow-Yang, C. W.; Sennaroglu, A.; Lechner, R. T.; Nizamoglu, S. Cadmium-Free and Efficient Type-II InP/ZnO/ZnS Quantum Dots and Their Application for LEDs. ACS Appl. Mater. Interfaces 2021, 13 (27), 32022– 32030, DOI: 10.1021/acsami.1c08118Google Scholar131https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhsVelt7jP&md5=fcdf82cc7f9bcfad6ceae00822697b26Cadmium-Free and Efficient Type-II InP/ZnO/ZnS Quantum Dots and Their Application for LEDsEren, Guncem Ozgun; Sadeghi, Sadra; Bahmani Jalali, Houman; Ritter, Maximilian; Han, Mertcan; Baylam, Isinsu; Melikov, Rustamzhon; Onal, Asim; Oz, Fatma; Sahin, Mehmet; Ow-Yang, Cleva W.; Sennaroglu, Alphan; Lechner, Rainer T.; Nizamoglu, SedatACS Applied Materials & Interfaces (2021), 13 (27), 32022-32030CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)It is a generally accepted perspective that type-II nanocrystal quantum dots (QDs) have low quantum yield due to the sepn. of the electron and hole wavefunctions. Recently, high quantum yield levels were reported for cadmium-based type-II QDs. Hence, the quest for finding non-toxic and efficient type-II QDs is continuing. Herein, we demonstrate environmentally benign type-II InP/ZnO/ZnS core/shell/shell QDs that reach a high quantum yield of ~ 91%. For this, ZnO layer was grown on core InP QDs by thermal decompn., which was followed by a ZnS layer via successive ionic layer adsorption. The small-angle X-ray scattering shows that spherical InP core and InP/ZnO core/shell QDs turn into elliptical particles with the growth of the ZnS shell. To conserve the quantum efficiency of QDs in device architectures, InP/ZnO/ZnS QDs were integrated in the liq. state on blue light-emitting diodes (LEDs) as down-converters that led to an external quantum efficiency of 9.4% and a power conversion efficiency of 6.8%, resp., which is the most efficient QD-LED using type-II QDs. This study pointed out that cadmium-free type-II QDs can reach high efficiency levels, which can stimulate novel forms of devices and nanomaterials for bioimaging, display, and lighting.
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132Yong, K. T.; Ding, H.; Roy, I.; Law, W. C.; Bergey, E. J.; Maitra, A.; Prasad, P. N. Imaging Pancreatic Cancer Using Bioconjugated Inp Quantum Dots. ACS Nano 2009, 3 (3), 502– 510, DOI: 10.1021/nn8008933Google Scholar132https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitlyrsbs%253D&md5=5695dde181f28ace6c4085a42d51a5f9Imaging Pancreatic Cancer Using Bioconjugated InP Quantum DotsYong, Ken-Tye; Ding, Hong; Roy, Indrajit; Law, Wing-Cheung; Bergey, Earl J.; Maitra, Anirban; Prasad, Paras N.ACS Nano (2009), 3 (3), 502-510CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)In this paper, the authors report the successful use of non-cadmium-based quantum dots (QDs) as highly efficient and nontoxic optical probes for imaging live pancreatic cancer cells. Indium phosphide (core)-zinc sulfide (shell), or InP/ZnS, QDs with high quality and bright luminescence were prepd. by a hot colloidal synthesis method in nonaq. media. The surfaces of these QDs were then functionalized with mercaptosuccinic acid to make them highly dispersible in aq. media. Further bioconjugation with pancreatic cancer specific monoclonal antibodies, such as anticlaudin 4 and antiprostate stem cell antigen (anti-PSCA), to the functionalized InP/ZnS QDs, allowed specific in vitro targeting of pancreatic cancer cell lines (both immortalized and low passage ones). The receptor-mediated delivery of the bioconjugates was further confirmed by the observation of poor in vitro targeting in nonpancreatic cancer based cell lines which are neg. for the claudin-4-receptor. These observations suggest the immense potential of InP/ZnS QDs as non-cadmium-based safe and efficient optical imaging nanoprobes in diagnostic imaging, particularly for early detection of cancer.
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133Lin, G.; Ouyang, Q.; Hu, R.; Ding, Z.; Tian, J.; Yin, F.; Xu, G.; Chen, Q.; Wang, X.; Yong, K. T. In Vivo Toxicity Assessment of Non-Cadmium Quantum Dots in BALB/c Mice. Nanomedicine Nanotechnology, Biol. Med. 2015, 11 (2), 341– 350, DOI: 10.1016/j.nano.2014.10.002Google Scholar133https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2MzjsVCisA%253D%253D&md5=689dea0989f9b6334082c4c58c1654e2In vivo toxicity assessment of non-cadmium quantum dots in BALB/c miceLin Guimiao; Ding Zhangchi; Tian Jinglin; Chen Qiang; Wang Xiaomei; Ouyang Qingling; Hu Rui; Yin Feng; Xu Gaixia; Yong Ken-TyeNanomedicine : nanotechnology, biology, and medicine (2015), 11 (2), 341-50 ISSN:.Along with widespread usage of QDs in electronic and biomedical industries, the likelihood of QDs exposure to the environment and humans is deemed to occur when the QD products are degraded or handled as waste for processing. To date, there are very few toxicological reports available in the literature for non-cadmium QDs in animal models. In this work, we studied the long term in vivo toxicity of InP/ZnS QDs in BALB/c mice. The biodistribution, body weight, hematology, blood biochemistry, and organ histology were determined at a very high dosage (25 mg/kg) of InP/ZnS QDs over 84 days period. Our results manifested that the QDs formulation did not result in observable toxicity in vivo within the evaluation period, thereby suggesting that the InP/ZnS QDs can be utilized as optical probes or nanocarrier for selected in vivo biological applications when an optimized dosage is employed. FROM THE CLINICAL EDITOR: This study investigated the toxicity of quantum dots in BALB/c mice, and concluded that no organotoxicity was detectable despite of using high concentration of InP/ZnS quantum dots with prolonged exposure of 3 months.
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134Van De Walle, C. G. Universal Alignment of Hydrogen Levels in Semiconductors and Insulators. Phys. B Condens. Matter 2006, 376–377 (1), 1– 6, DOI: 10.1016/j.physb.2005.12.004Google Scholar134https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XivVGntb0%253D&md5=e06f62d413308d0bc80abfa71fff3babUniversal alignment of hydrogen levels in semiconductors and insulatorsVan de Walle, Chris G.Physica B: Condensed Matter (Amsterdam, Netherlands) (2006), 376-377 (), 1-6CODEN: PHYBE3; ISSN:0921-4526. (Elsevier B.V.)H strongly affects the properties of electronic materials. It is always elec. active, and usually counteracts the prevailing cond. of the semiconductor. In some materials, however, H acts as a source of doping. We have developed a model that enables us to predict the elec. activity of H in any material, based on its band alignment on an abs. energy scale. We discuss the underlying physics, as well as consequences for specific materials, including ZnO and GaN.
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135Shankara Narayanan, S.; Sinha, S. S.; Verma, P. K.; Pal, S. K. Ultrafast Energy Transfer from 3-Mercaptopropionic Acid-Capped CdSe/ZnS QDs to Dye-Labelled DNA. Chem. Phys. Lett. 2008, 463 (1–3), 160– 165, DOI: 10.1016/j.cplett.2008.08.057Google ScholarThere is no corresponding record for this reference.
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136Sada, N.; Lee, S.; Katsu, T.; Otsuki, T.; Inoue, T. Targeting LDH Enzymes with a Stiripentol Analog to Treat Epilepsy. Science (80-.). 2015, 347 (6228), 1362– 1367, DOI: 10.1126/science.aaa1299Google ScholarThere is no corresponding record for this reference.
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137Han, X.; Boyden, E. S. Multilpe-Color Optical Activation, Silencing, and Desynchronization of Neural Activity, with Single-Spike Temporal Resolution. PLoS One 2007, 2 (3), e299 DOI: 10.1371/journal.pone.0000299Google ScholarThere is no corresponding record for this reference.
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138Han, M.; Srivastava, S. B.; Yildiz, E.; Melikov, R.; Surme, S.; Dogru-Yuksel, I. B.; Kavakli, I. H.; Sahin, A.; Nizamoglu, S. Organic Photovoltaic Pseudocapacitors for Neurostimulation. ACS Appl. Mater. Interfaces 2020, 12 (38), 42997– 43008, DOI: 10.1021/acsami.0c11581Google Scholar138https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhs12rtrzF&md5=1a37a254c83b8159bae70b6f77168a78Organic Photovoltaic Pseudocapacitors for NeurostimulationHan, Mertcan; Srivastava, Shashi Bhushan; Yildiz, Erdost; Melikov, Rustamzhon; Surme, Saliha; Dogru-Yuksel, Itir Bakis; Kavakli, Ibrahim Halil; Sahin, Afsun; Nizamoglu, SedatACS Applied Materials & Interfaces (2020), 12 (38), 42997-43008CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Neural interfaces are the fundamental tools to understand the brain and cure many nervous-system diseases. For proper interfacing, seamless integration, efficient and safe digital-to-biol. signal transduction, and long operational lifetime are required. Here, we devised a wireless optoelectronic pseudocapacitor converting the optical energy to safe capacitive currents by dissocg. the photogenerated excitons in the photovoltaic unit and effectively routing the holes to the supercapacitor electrode and the pseudocapacitive electrode-electrolyte interfacial layer of PEDOT:PSS for reversible faradic reactions. The biointerface showed high peak capacitive currents of ~ 3 mA·cm-2 with total charge injection of ~ 1μC·cm-2 at responsivity of 30 mA·W-1, generating high photovoltages over 400 mV for the main eye photoreception colors of blue, green, and red. Moreover, modification of PEDOT:PSS controls the charging/discharging phases leading to rapid capacitive photoresponse of 50μs and effective membrane depolarization at the single-cell level. The neural interface has a device lifetime of over 1.5 years in the aq. environment and showed stability without significant performance decrease after sterilization steps. Our results demonstrate that adopting the pseudocapacitance phenomenon on org. photovoltaics paves an ultraefficient, safe, and robust way toward communicating with biol. systems.
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139Yang, Y.; Zhang, Z. G.; Bin, H.; Chen, S.; Gao, L.; Xue, L.; Yang, C.; Li, Y. Side-Chain Isomerization on an n-Type Organic Semiconductor ITIC Acceptor Makes 11.77% High Efficiency Polymer Solar Cells. J. Am. Chem. Soc. 2016, 138 (45), 15011– 15018, DOI: 10.1021/jacs.6b09110Google Scholar139https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhslCgsLrP&md5=54040cde48b96af634ca492f9bf79198Side-Chain Isomerization on an n-type Organic Semiconductor ITIC Acceptor Makes 11.77% High Efficiency Polymer Solar CellsYang, Yankang; Zhang, Zhi-Guo; Bin, Haijun; Chen, Shanshan; Gao, Liang; Xue, Lingwei; Yang, Changduk; Li, YongfangJournal of the American Chemical Society (2016), 138 (45), 15011-15018CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Low bandgap n-type org. semiconductor (n-OS) ITIC has attracted great attention for the application as an acceptor with medium bandgap p-type conjugated polymer as donor in nonfullerene polymer solar cells (PSCs) because of its attractive photovoltaic performance. Here the authors report a modification on the mol. structure of ITIC by side-chain isomerization with meta-alkyl-Ph substitution, m-ITIC, to further improve its photovoltaic performance. In a comparison with its isomeric counterpart ITIC with para-alkyl-Ph substitution, m-ITIC shows a higher film absorption coeff., a larger cryst. coherence, and higher electron mobility. These inherent advantages of m-ITIC resulted in a higher power conversion efficiency (PCE) of 11.77% for the nonfullerene PSCs with m-ITIC as acceptor and a medium bandgap polymer J61 as donor, which is significantly improved over that (10.57%) of the corresponding devices with ITIC as acceptor. The PCE of 11.77% is one of the highest values reported in the literature to date for nonfullerene PSCs. More importantly, the m-ITIC-based device shows less thickness-dependent photovoltaic behavior than ITIC-based devices in the active-layer thickness range of 80-360 nm, which is beneficial for large area device fabrication. M-ITIC is a promising low bandgap n-OS for the application as an acceptor in PSCs, and the side-chain isomerization could be an easy and convenient way to further improve the photovoltaic performance of the donor and acceptor materials for high efficiency PSCs.
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140Kramer, I. J.; Sargent, E. H. The Architecture of Colloidal Quantum Dot Solar Cells: Materials to Devices. Chem. Rev. 2014, 114 (1), 863– 882, DOI: 10.1021/cr400299tGoogle Scholar140https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVygu7bN&md5=ccf7ecc0222c6ee778776ec0921db5c5The Architecture of Colloidal Quantum Dot Solar Cells: Materials to DevicesKramer, Illan J.; Sargent, Edward H.Chemical Reviews (Washington, DC, United States) (2014), 114 (1), 863-882CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review; architecture of colloidal quantum dot solar cells materials to devices is discussed.
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141Johnston, K. W.; Pattantyus-Abraham, A. G.; Clifford, J. P.; Myrskog, S. H.; Hoogland, S.; Shukla, H.; Klem, E. J. D.; Levina, L.; Sargent, E. H. Efficient Schottky-Quantum-Dot Photovoltaics: The Roles of Depletion, Drift, and Diffusion. Appl. Phys. Lett. 2008, 92 (12), 122111, DOI: 10.1063/1.2896295Google Scholar141https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXksF2rs7w%253D&md5=1f29db298d229c16a68a16ccc12a5906Efficient Schottky-quantum-dot photovoltaics. The roles of depletion, drift, and diffusionJohnston, Keith W.; Pattantyus-Abraham, Andras G.; Clifford, Jason P.; Myrskog, Stefan H.; Hoogland, Sjoerd; Shukla, Harnik; Klem, Ethan J. D.; Levina, Larissa; Sargent, Edward H.Applied Physics Letters (2008), 92 (12), 122111/1-122111/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)PbS colloidal quantum dot photovoltaic devices in a Schottky architecture have demonstrated an IR power conversion efficiency of 4.2%. Here, we elucidate the internal mechanisms leading to this efficiency. At relevant intensities, the drift length is 10 μm for holes and 1 μm for electrons. Transport within the 150 nm wide depletion region is therefore highly efficient. The electron diffusion length of 0.1 μm is comparable to neutral region width. We quant. account for the obsd. 37% external quantum efficiency, showing that it results from the large depletion width and long carrier lifetime combined. (c) 2008 American Institute of Physics.
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142Parameswaran, R.; Carvalho-De-Souza, J. L.; Jiang, Y.; Burke, M. J.; Zimmerman, J. F.; Koehler, K.; Phillips, A. W.; Yi, J.; Adams, E. J.; Bezanilla, F.; Tian, B. Photoelectrochemical Modulation of Neuronal Activity with Free-Standing Coaxial Silicon Nanowires. Nat. Nanotechnol. 2018, 13 (3), 260– 266, DOI: 10.1038/s41565-017-0041-7Google Scholar142https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjtFKqu7g%253D&md5=13d95a520bfecbbcefba44e4c5a27d80Photoelectrochemical modulation of neuronal activity with free-standing coaxial silicon nanowiresParameswaran, Ramya; Carvalho-de-Souza, Joao L.; Jiang, Yuanwen; Burke, Michael J.; Zimmerman, John F.; Koehler, Kelliann; Phillips, Andrew W.; Yi, Jaeseok; Adams, Erin J.; Bezanilla, Francisco; Tian, BozhiNature Nanotechnology (2018), 13 (3), 260-266CODEN: NNAABX; ISSN:1748-3387. (Nature Research)Optical methods for modulating cellular behavior are promising for both fundamental and clin. applications. However, most available methods are either mech. invasive, require genetic manipulation of target cells or cannot provide subcellular specificity. Here, we address all these issues by showing optical neuromodulation with free-standing coaxial p-type/intrinsic/n-type silicon nanowires. We reveal the presence of at. gold on the nanowire surfaces, likely due to gold diffusion during the material growth. To evaluate how surface gold impacts the photoelectrochem. properties of single nanowires, we used modified quartz pipettes from a patch clamp and recorded sustained cathodic photocurrents from single nanowires. We show that these currents can elicit action potentials in primary rat dorsal root ganglion neurons through a primarily at. gold-enhanced photoelectrochem. process.
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143Lv, H.; Wang, C.; Li, G.; Burke, R.; Krauss, T. D.; Gao, Y.; Eisenberg, R. Semiconductor Quantum Dot-Sensitized Rainbow Photocathode for Effective Photoelectrochemical Hydrogen Generation. Proc. Natl. Acad. Sci. U. S. A. 2017, 114 (43), 11297– 11302, DOI: 10.1073/pnas.1712325114Google Scholar143https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1aju7fL&md5=2871717e6e7517fa1ee6af1f3edee645Semiconductor quantum dot-sensitized rainbow photocathode for effective photoelectrochemical hydrogen generationLv, Hongjin; Wang, Congcong; Li, Guocan; Burke, Rebeckah; Krauss, Todd D.; Gao, Yongli; Eisenberg, RichardProceedings of the National Academy of Sciences of the United States of America (2017), 114 (43), 11297-11302CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The present study reports the fabrication of CdSe quantum dot (QD)-sensitized photocathodes on NiO-coated In Sn oxide (ITO) electrodes and their H2-generating ability upon light irradn. A well-established spin-coating method was used to deposit CdSe QD stock soln. onto the surface of NiO/ITO electrodes, thereby leading to the construction of various CdSe QD-sensitized photocathodes. The present report includes the construction of rainbow photocathodes by spin-coating different-sized QDs in a sequentially layered manner, thereby creating an energetically favorable gradient for charge sepn. The resulting rainbow photocathodes with forward energetic gradient for charge sepn. and subsequent electron transfer to a soln.-based H-evolving catalyst (HEC) exhibit good light-harvesting ability and enhanced photo-responses compared with the reverse rainbow photocathodes under white LED light illumination. Under minimally optimized conditions, a photocurrent d. of ≤115 μA cm-2 and a faradaic efficiency of 99.5% are achieved, which is among the most effective QD-based photocathode H2O-splitting systems.
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144Mirkovic, T.; Ostroumov, E. E.; Anna, J. M.; Van Grondelle, R.; Govindjee; Scholes, G. D. Light Absorption and Energy Transfer in the Antenna Complexes of Photosynthetic Organisms. Chem. Rev. 2017, 117 (2), 249– 293, DOI: 10.1021/acs.chemrev.6b00002Google Scholar144https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFyit7vI&md5=7201884bb63ab70347f79f951ff3369aLight absorption and energy transfer in the antenna complexes of photosynthetic organismsMirkovic, Tihana; Ostroumov, Evgeny E.; Anna, Jessica M.; van Grondelle, Rienk; Govindjee; Scholes, Gregory D.Chemical Reviews (Washington, DC, United States) (2017), 117 (2), 249-293CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing mols. (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solns. for light harvesting. In this review, we describe the underlying photophys. principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET). First, optical properties of the individual pigment chromophores present in light-harvesting antenna complexes are introduced, and then we examine the collective behavior of pigment-pigment and pigment-protein interactions. The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment mols. In the latter half of the article, we focus on the light-harvesting complexes of purple bacteria as a model to illustrate the present understanding of the synergetic effects leading to EET optimization of light-harvesting antenna systems while exploring the structure and function of the integral chromophores. We end this review with a brief overview of the energy-transfer dynamics and pathways in the light-harvesting antennas of various photosynthetic organisms.
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145Bahmani Jalali, H.; Melikov, R.; Sadeghi, S.; Nizamoglu, S. Excitonic Energy Transfer within InP/ZnS Quantum Dot Langmuir-Blodgett Assemblies. J. Phys. Chem. C 2018, 122 (22), 11616– 11622, DOI: 10.1021/acs.jpcc.8b00744Google Scholar145https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXptVCjsbk%253D&md5=c3b61852bb2f2992698c6714e6cc4314Excitonic Energy Transfer within InP/ZnS Quantum Dot Langmuir-Blodgett AssembliesBahmani Jalali, Houman; Melikov, Rustamzhon; Sadeghi, Sadra; Nizamoglu, SedatJournal of Physical Chemistry C (2018), 122 (22), 11616-11622CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)InP/ZnS core/shell quantum dot monolayers were assembled via the Langmuir-Blodgett technique, and the effect of ZnS shell thickness on the excitonic energy transfer within these core/shell quantum dots was studied. Three types of InP-based core/shell quantum dot Langmuir-Blodgett assemblies with different ZnS shell thicknesses were assembled. The structural and optical properties of colloidal quantum dots reveal the successful multiple ZnS shell growth, and at. force microscopy studies show the smoothness of the assembled monolayers. Time-resolved luminescence (PL) and fluorescence lifetime imaging microscopy (FLIM) studies of the thick-shell QD monolayer reveal narrower lifetime distribution in comparison with the thin-shell QD monolayer. The interparticle excitonic energy transfer was studied by spectrally resolved PL traces, and higher energy transfer was obsd. for the thin-shell InP/1ZnS QD monolayer. Finally, the authors calcd. the av. exciton energy and indicated that the energy transfer induced exciton energy shift decreased significantly from 95 to 27 meV after multiple ZnS shell growth.
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146Kumar, B. G.; Sadeghi, S.; Melikov, R.; Aria, M. M.; Jalali, H. B.; Ow-Yang, C. W.; Nizamoglu, S. Structural Control of InP/ZnS Core/Shell Quantum Dots Enables High-Quality White LEDs. Nanotechnology 2018, 29 (34), 345605, DOI: 10.1088/1361-6528/aac8c9Google Scholar146https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisVansLnF&md5=64d5b1b83ce61f5071eab797fd77d85cStructural control of InP/ZnS core/shell quantum dots enables high-quality white LEDsKumar, Baskaran Ganesh; Sadeghi, Sadra; Melikov, Rustamzhon; Aria, Mohammad Mohammadi; Jalali, Houman Bahmani; Ow-Yang, Cleva W.; Nizamoglu, SedatNanotechnology (2018), 29 (34), 345605/1-345605/9CODEN: NNOTER; ISSN:1361-6528. (IOP Publishing Ltd.)Herein, we demonstrate that the structural and optical control of InP-based quantum dots (QDs) can lead to high-performance light-emitting diodes (LEDs). Zinc sulfide (ZnS) shells passivate the InP QD core and increase the quantum yield in green-emitting QDs by 13-fold and redemitting QDs by 8-fold. The optimized QDs are integrated in the liq. state to eliminate aggregation-induced emission quenching and we fabricated white LEDs with a warm, neutral and cool-white appearance by the down-conversion mechanism. The QD-functionalized white LEDs achieve luminous efficiency (LE) up to 14.7 lmW-1 and color-rendering index up to 80. The structural and optical control of InP/ZnS core/shell QDs enable 23-fold enhancement in LE of white LEDs compared to ones contg. only QDs of InP core.
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147Achermann, M.; Petruska, M. A.; Crooker, S. A.; Klimov, V. I. Picosecond Energy Transfer in Quantum Dot Langmuir - Blodgett Nanoassemblies. J. Phys. Chem. B 2003, 107 (50), 13782– 13787, DOI: 10.1021/jp036497rGoogle Scholar147https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXptVKntL0%253D&md5=4e530b22ec2c71a4c74d6881c3905cc0Picosecond Energy Transfer in Quantum Dot Langmuir-Blodgett NanoassembliesAchermann, Marc; Petruska, Melissa A.; Crooker, Scott A.; Klimov, Victor I.Journal of Physical Chemistry B (2003), 107 (50), 13782-13787CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)The authors study spectrally resolved dynamics of Forster energy transfer in single monolayers and bilayers of semiconductor nanocrystal quantum dots assembled using Langmuir-Blodgett (LB) techniques. For a single monolayer, the authors observe a distribution of transfer times from ∼50 ps to ∼10 ns, which can be quant. modeled assuming that the energy transfer is dominated by interactions of a donor nanocrystal with acceptor nanocrystals from the 1st 3 shells surrounding the donor. The authors also detect an effective enhancement of the absorption cross section (up to a factor of 4) for larger nanocrystals on the red side of the size distribution, which results from strong, interdot electrostatic coupling in the LB film (the light-harvesting antenna effect). By assembling bilayers of nanocrystals of 2 different sizes, the authors are able to improve the donor-acceptor spectral overlap for engineered transfer in a specific (vertical) direction. These bilayers show a fast, unidirectional energy flow with a time const. of ∼120 ps.
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148Jin, F.; Zheng, M. L.; Liu, Z. H.; Fan, Y. M.; Xu, K.; Zhao, Z. S.; Duan, X. M. Layer-by-Layer Assembled PMMA-SH/CdSe-Au Nanocomposite Thin Films and the Optical Limiting Property. RSC Adv. 2016, 6 (30), 25401– 25408, DOI: 10.1039/C6RA02893DGoogle Scholar148https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XjsVeitLY%253D&md5=21ba426bdb55d5876fc3be605d7a444bLayer-by-layer assembled PMMA-SH/CdSe-Au nanocomposite thin films and the optical limiting propertyJin, Feng; Zheng, Mei-Ling; Liu, Zheng-Hui; Fan, Yi-Ming; Xu, Ke; Zhao, Zhen-Sheng; Duan, Xuan-MingRSC Advances (2016), 6 (30), 25401-25408CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)PMMA-SH/CdSe-Au nanocomposite thin films have been constructed by a layer-by-layer (LBL) assembly method. The LBL assembly process is carried out in a nonpolar solvent by the combination of photopolymn. and adsorption of CdSe-Au nanoparticles. Absorption spectra suggest that the LBL assembly is performed in a stepwise and uniform way. The optical, morphol., thermal, and optical limiting properties of the resultant PMMA-SH/CdSe-Au nanocomposite thin films are characterized by transmission, TEM, TGA and laser measurements. The LBL assembled PMMA-SH/CdSe-Au nanocomposite thin films exhibit good thermal stability, transparency, and optical limiting response to a 532 nm pulsed laser. The optical limiting threshold of the PMMA-SH/CdSe-Au nanocomposite thin film is 13 J cm-2. This study provides a robust and efficient strategy for fabricating transparent polymeric thin films with laser optical limiting property.
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149Nordlander, P.; Oubre, C.; Prodan, E.; Li, K.; Stockman, M. I. Plasmon Hybridization in Nanoparticle Dimers. Nano Lett. 2004, 4 (5), 899– 903, DOI: 10.1021/nl049681cGoogle Scholar149https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjtVWjtb8%253D&md5=ea84018ef7760e1f23687ba25aaab488Plasmon Hybridization in Nanoparticle DimersNordlander, P.; Oubre, C.; Prodan, E.; Li, K.; Stockman, M. I.Nano Letters (2004), 4 (5), 899-903CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)The recently developed plasmon hybridization method was applied to nanoparticle dimers, providing a simple and intuitive description of how the energy and excitation cross sections of dimer plasmons depend on nanoparticle sepn. The dimer plasmons can be viewed as bonding and antibonding combinations, i.e., hybridization of the individual nanoparticle plasmons. The calcd. plasmon energies are compared with results from finite difference time domain simulations.
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150Borchert, H.; Haubold, S.; Haase, M.; Weller, H.; McGinley, C.; Riedler, M.; Möller, T. Investigation of ZnS Passivated InP Nanocrystals by XPS. Nano Lett. 2002, 2 (2), 151– 154, DOI: 10.1021/nl0156585Google Scholar150https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovF2mur4%253D&md5=5ebc94aac466d061bae182ec64fd8608Investigation of ZnS Passivated InP Nanocrystals by XPSBorchert, Holger; Haubold, Stephan; Haase, Markus; Weller, Horst; McGinley, Colm; Riedler, Manfred; Moeller, ThomasNano Letters (2002), 2 (2), 151-154CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)ZnS passivated InP nanoparticles prepd. by the TOP/TOPO method have been investigated by photoelectron spectroscopy with tunable synchrotron radiation. Based on the energy dependence of the electron escape depth, we present a method to characterize the core-shell nature of the sample structure. Energy tuning indicates that In is confined to the core of the particles while Zn is located in a surrounding shell. Computer simulation allows us to quantify these results and to ext. av. layer thicknesses.
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151Şahin, M.; Nizamoglu, S.; Kavruk, A. E.; Demir, H. V. Self-Consistent Computation of Electronic and Optical Properties of a Single Exciton in a Spherical Quantum Dot via Matrix Diagonalization Method. J. Appl. Phys. 2009, 106 (4), 043704, DOI: 10.1063/1.3197034Google Scholar151https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVeqt7bF&md5=e447a60dda5fa07a2f69f495b18b780fSelf-consistent computation of electronic and optical properties of a single exciton in a spherical quantum dot via matrix diagonalization methodSahin, Mehmet; Nizamoglu, Sedat; Kavruk, A. Emre; Demir, Hilmi VolkanJournal of Applied Physics (2009), 106 (4), 043704/1-043704/5CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)In this study, we develop and demonstrate an efficient self-consistent calcn. schema that computes the electronic structure and optical properties of a single exciton in a spherical quantum dot (QD) with an interacting pair of electron and hole wave functions. To observe modifications on bands, wave functions, and energies due to the attractive Coulomb potential, the full numeric matrix diagonalization technique is employed to det. sublevel energy eigenvalues and their wave functions in effective mass approxn. This treatment allows to observe that the conduction and valence band edges bend, that the electron and hole wave functions strongly localize in the QD, and that the excitonic energy level exhibits red shift. In our approach for the Coulomb term between electron and hole, the Poisson-Schroedinger equations are solved self-consistently in the Hartree approxn. Subsequently, exciton binding energies and assocd. optical properties are computed. The results are presented as a function of QD radii and photon energies. We conclude that all of these numerical results are in agreement with the exptl. studies. (c) 2009 American Institute of Physics.
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152Gong, X.; Tong, M.; Brunetti, F. G.; Seo, J.; Sun, Y.; Moses, D.; Wudl, F.; Heeger, A. J. Bulk Heterojunction Solar Cells with Large Open-Circuit Voltage: Electron Transfer with Small Donor-Acceptor Energy Offset. Adv. Mater. 2011, 23 (20), 2272– 2277, DOI: 10.1002/adma.201003768Google Scholar152https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXms1SktLs%253D&md5=a0730c4fed90fb7562515e800e738e9dBulk Heterojunction Solar Cells with Large Open-Circuit Voltage and Electron Transfer with Small Donor-Acceptor Energy OffsetGong, Xiong; Tong, Minghong; Brunetti, Fulvio G.; Seo, Junghwa; Sun, Yanming; Moses, Daniel; Wudl, Fred; Heeger, Alan J.Advanced Materials (Weinheim, Germany) (2011), 23 (20), 2272-2277CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors characterized the new electron acceptor D99'BF and the P3HT:D99'BF bulk heterojunction (BHJ) material, showing that D99'BF exhibits strong optical absorption over the spectral range from 4 eV to 1.9 eV, and increases the optical d. and improves the light harvesting in this spec-tral range when it is blended with P3HT. Ultrafast charge transfer and charge sepn. are demonstrated in P3HT:D99'BF BHJ films, and photoinduced electron transfer from P3HT to the D99'BF yields mobile carriers with long lifetimes. It was demonstrated that electron transfer occurs even though ELUMO(P3HT)-ELUMO(D99'BF) = 0.12 eV. indicating that large LUMO band offsets are not required for charge sepn., and the exciton binding energy in P3HT must be less than approx. 0.1 eV. BHJ PSCs fabricated using P3HT:D99'BF phase sepd. composites exhibit an open circuit voltage, Voc = 1.20 V (under AM 1.5 solar radiation), close to the theor. max. estd. from the difference in the energy levels of the HOMO of P3HT and LUMO of D99'BF, indicating that Voc values close to the band gap of the semiconducting polymer should be possible for BHJ PSCs just as for inorg. solar cells.
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153Cao, Y.; Stavrinadis, A.; Lasanta, T.; So, D.; Konstantatos, G. The Role of Surface Passivation for Efficient and Photostable PbS Quantum Dot Solar Cells. Nat. Energy 2016, 1 (4), 16035, DOI: 10.1038/nenergy.2016.35Google Scholar153https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVekurk%253D&md5=e0ffcf8f062cb920cc708d564109e047The role of surface passivation for efficient and photostable PbS quantum dot solar cellsCao, Yiming; Stavrinadis, Alexandros; Lasanta, Tania; So, David; Konstantatos, GerasimosNature Energy (2016), 1 (4), 16035CODEN: NEANFD; ISSN:2058-7546. (Nature Publishing Group)For any emerging photovoltaic technol. to become com. relevant, both its power conversion efficiency and photostability are key parameters to be fulfilled. Colloidal quantum dot solar cells are a soln.-processed, low-cost technol. that has reached an efficiency of about 9% by judiciously controlling the surface of the quantum dots to enable surface passivation and tune energy levels. However, the role of the quantum dot surface on the stability of these solar cells has remained elusive. Here we report on highly efficient and photostable quantum dot solar cells with efficiencies of 9.6% (and independently certificated values of 8.7%). As a result of optimized surface passivation and the suppression of hydroxyl ligands-which are found to be detrimental for both efficiency and photostability-the efficiency remains within 80% of its initial value after 1,000 h of continuous illumination at AM1.5G. Our findings provide insights into the role of the quantum dot surface in both the stability and efficiency of quantum dot solar cells.
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154Durmusoglu, E. G.; Selopal, G. S.; Mohammadnezhad, M.; Zhang, H.; Dagtepe, P.; Barba, D.; Sun, S.; Zhao, H.; Acar, H. Y.; Wang, Z. M.; Rosei, F. Low-Cost, Air-Processed Quantum Dot Solar Cells via Diffusion-Controlled Synthesis. ACS Appl. Mater. Interfaces 2020, 12 (32), 36301– 36310, DOI: 10.1021/acsami.0c06694Google Scholar154https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtl2jur%252FE&md5=787c9bc3937e38f8228bddc38d59541cLow-Cost, Air-Processed Quantum Dot Solar Cells via Diffusion-Controlled SynthesisDurmusoglu, Emek G.; Selopal, Gurpreet S.; Mohammadnezhad, Mahyar; Zhang, Hui; Dagtepe, Pinar; Barba, David; Sun, Shuhui; Zhao, Haiguang; Acar, Havva Yagci; Wang, Zhiming M.; Rosei, FedericoACS Applied Materials & Interfaces (2020), 12 (32), 36301-36310CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Despite significant advances in the development of high-efficiency and stable quantum dot (QD) solar cells (QDSCs), recent synthetic and fabrication routes still require improvements to render QDSCs com. feasible. Here, we describe a low-cost, industrially viable fabrication method of QDSCs under an ambient atm. (humid air and room temp.) using stable, high-quality, and small-sized PbS QDs prepd. with low-cost, greener precursors [i.e., thioacetamide (TAA)] compared to the widely used bis(trimethylsilyl)sulfide [(TMS)2S], at low temps. without requiring any stringent conditions. The low reaction temp., medium reactivity of TAA, and diffusion-controlled particle growth adopted in this approach provide an opportunity to synthesize ultrasmall (emission peak ~ 700 nm) to larger PbS QDs (emission peak ~ 1050 nm). This also enables well-controlled large-scale (multigram) synthesis with a rough estd. prodn. cost of PbS of 8.11 $ per g (based on materials cost), which is the lowest among the available PbS QDs produced using wet chem. routes. QDSCs fabricated using 3.25 nm PbS QDs (bandgap 1.29 eV) under ambient conditions yield a high circuit c.d. (Jsc) of 32.4 mA/cm2 (one of the highest values of Jsc ever reported) with a power conversion efficiency of 7.8% under 1 sun simulated sunlight at AM 1.5 G (100 mW/cm2). These devices exhibit better photovoltaic performance compared to devices fabricated with more traditional PbS QDs synthesized with (TMS)2S under an ambient atm., confirming the quality of PbS QDs produced with our method. The diffusion-controlled TAA-based synthetic route developed herein is found to be very promising for synthesizing size-tunable PbS QDs for photovoltaic and other optoelectronic applications.
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155Corna, A.; Herrmann, T.; Zeck, G. Electrode-Size Dependent Thresholds in Subretinal Neuroprosthetic Stimulation. J. Neural Eng. 2018, 15 (4), 045003, DOI: 10.1088/1741-2552/aac1c8Google Scholar155https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MjovFaitA%253D%253D&md5=bb689e644e0098843cd7edc18a853e81Electrode-size dependent thresholds in subretinal neuroprosthetic stimulationCorna Andrea; Herrmann Thoralf; Zeck GuntherJournal of neural engineering (2018), 15 (4), 045003 ISSN:.OBJECTIVE: Retinal prostheses have shown promising results in restoring some visual perception to blind patients but successful identification of objects of different size remains a challenge. Here we investigated electrode-size specific stimulation thresholds and their variability for subretinal electrical stimulation. Our findings indicate the range of charge densities required to achieve identification of small objects and the object-size-specific scaling of stimulation threshold. APPROACH: Using biphasic voltage-limited current stimuli provided by a light-sensitive microchip, we determined threshold charge densities for stimulation with variable electrode sizes. The stimulated activation of the retinal network was identified by recording the spiking of retinal ganglion cells in photoreceptor-degenerated mouse rd10 retinas. Stimulation thresholds were determined for cells with saturating stimulus response relationships (SRRs) but not for cells characterized by monotonically increasing or decreasing SRRs. MAIN RESULTS: Stimulation thresholds estimated in rd10 retinas ranged between 100-900 μC cm(-2) for stimulation with small electrodes (30 μm diameter). Threshold charge density decreased with increasing electrode size and plateaued at 20 μC cm(-2) for an electrode diameter larger than 300 μm. This trend of decreasing threshold down to a plateau value was confirmed in wild-type mouse retina suggesting an underlying physiological source. SIGNIFICANCE: Our results suggest the following guidelines for retinal prosthetics employing biphasic current pulses. The encoding of small objects may be achieved through the activation of a confined set of different retinal ganglion cells, with individual stimulation thresholds spanning a wide range of charge densities. The encoding of increasing object sizes may be achieved by decreasing stimulation charge density.
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156Bahmani Jalali, H.; Sadeghi, S.; Sahin, M.; Ozturk, H.; Ow-Yang, C. W.; Nizamoglu, S. Colloidal Aluminum Antimonide Quantum Dots. Chem. Mater. 2019, 31 (13), 4743– 4747, DOI: 10.1021/acs.chemmater.9b00905Google Scholar156https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtFaqtrnE&md5=a1d505509f3bfd0c89a64bc2e0f00fa1Colloidal Aluminum Antimonide Quantum DotsBahmani Jalali, Houman; Sadeghi, Sadra; Sahin, Mehmet; Ozturk, Hande; Ow-Yang, Cleva W.; Nizamoglu, SedatChemistry of Materials (2019), 31 (13), 4743-4747CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)AlSb is a less studied member of the III-V semiconductor family, and herein, we report the colloidal synthesis of AlSb quantum dots (QDs) for the first time. Different sizes of colloidal AlSb QDs (5 to 9 nm) were produced by the controlled reaction of AlCl3 and Sb[N(Si(Me)3)2]3 in the presence of superhydride. These colloidal AlSb quantum dots showed excitonic transitions in the UV-A region and a tunable band-edge emission (quantum yield of up to 18%) in the blue spectral range. Among all III-V quantum dots, these quantum dots show the brightest core emission in the blue spectral region.
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157Linnebach, R.; Benz, K. W. Bridgman Growth of AlSb. J. Cryst. Growth 1981, 53 (3), 579– 585, DOI: 10.1016/0022-0248(81)90142-1Google Scholar157https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXksFartLw%253D&md5=cf85e1ef72a4e563050ca6f75e53ce8fBridgman growth of aluminum antimonideLinnebach, R.; Benz, K. W.Journal of Crystal Growth (1981), 53 (3), 579-85CODEN: JCRGAE; ISSN:0022-0248.Crystals of undoped AlSb were grown from Sb-rich solns. at temps. < 1250 K using the Bridgman method. C crucibles inserted in sealed silica ampuls filled with Ar at low pressure gave the best results. High resistivity (ρ ≃ 200-600 Ω-cm) polycryst. material without any voids could be synthesized. Crystals grown at low temp. were particularly resistant to corrosion. Schottky barriers with reverse currents of < 0.5 μA/mm2 at 1 V could be prepd. in undoped p-type AlSb.
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158Schwartz, G. P.; Gualtieri, G. J.; Sunder, W. A.; Farrow, L. A. Light Scattering from Quantum Confined and Interface Optical Vibrational Modes in Strained-Layer GaSb/AlSb Superlattices. Phys. Rev. B 1987, 36 (9), 4868– 4877, DOI: 10.1103/PhysRevB.36.4868Google Scholar158https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2sXmtVOrs7s%253D&md5=9724b96b84d81afa715d88eeaea26805Light scattering from quantum confined and interface optical vibrational modes in strained-layer gallium antimonide/aluminum antimonide superlatticesSchwartz, G. P.; Gualtieri, G. J.; Sunder, W. A.; Farrow, L. A.Physical Review B: Condensed Matter and Materials Physics (1987), 36 (9), 4868-77CODEN: PRBMDO; ISSN:0163-1829.Raman scattering was performed on GaSb/AlSb strained-layer superlattices with periods varying from 65 to 300 Å. Discrete quantum confined GaSb longitudinal optical phonons were obsd. in GaSb layers at <25 Å thick. The confinement-induced Γ-to-L crossover in GaSb manifests itself in the spectra via the observation of optical-phonon d.-of-states structure. This structure disappears for GaSb layers thicker than 50 Å. Spatially extended interface modes were obsd. in all superlattices in both the GaSb and AlSb optical-mode spectra.
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159Barate, D.; Teissier, R.; Wang, Y.; Baranov, A. N. Short Wavelength Intersubband Emission from InAs/AlSb Quantum Cascade Structures. Appl. Phys. Lett. 2005, 87 (5), 051103, DOI: 10.1063/1.2007854Google Scholar159https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXnvVSnur0%253D&md5=599d631e809721fee580c8d6cffb0cc7Short wavelength intersubband emission from InAs/AlSb quantum cascade structuresBarate, D.; Teissier, R.; Wang, Y.; Baranov, A. N.Applied Physics Letters (2005), 87 (5), 051103/1-051103/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The InAs/AlSb material system is a promising candidate for the development of short wavelength quantum cascade lasers because of the large conduction band offset of 2.1 eV. The authors present a study of room temp. electroluminescence of InAs/AlSb quantum cascade structures as a function of the emission wavelength. Intersubband emission with a transition energy of 500 meV (λ=2.5 μm) was obtained.
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160Classen, A.; Chochos, C. L.; Lüer, L.; Gregoriou, V. G.; Wortmann, J.; Osvet, A.; Forberich, K.; McCulloch, I.; Heumüller, T.; Brabec, C. J. The Role of Exciton Lifetime for Charge Generation in Organic Solar Cells at Negligible Energy-Level Offsets. Nat. Energy 2020, 5 (9), 711– 719, DOI: 10.1038/s41560-020-00684-7Google Scholar160https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhvF2ksrjM&md5=e0217198005d63dc8e92e64031ba6f25The role of exciton lifetime for charge generation in organic solar cells at negligible energy-level offsetsClassen, Andrej; Chochos, Christos L.; Lueer, Larry; Gregoriou, Vasilis G.; Wortmann, Jonas; Osvet, Andres; Forberich, Karen; McCulloch, Iain; Heumueller, Thomas; Brabec, Christoph J.Nature Energy (2020), 5 (9), 711-719CODEN: NEANFD; ISSN:2058-7546. (Nature Research)Org. solar cells utilize an energy-level offset to generate free charge carriers. Although a very small energy-level offset increases the open-circuit voltage, it remains unclear how exactly charge generation is affected. Here we investigate org. solar cell blends with HOMO energy-level offsets (ΔEHOMO) between the donor and acceptor that range from 0 to 300 meV. We demonstrate that exciton quenching at a negligible ΔEHOMO takes place on timescales that approach the exciton lifetime of the pristine materials, which drastically limits the external quantum efficiency. We quant. describe this finding via the Boltzmann stationary-state equil. between charge-transfer states and excitons and further reveal a long exciton lifetime to be decisive in maintaining an efficient charge generation at a negligible ΔEHOMO. Moreover, the Boltzmann equil. quant. describes the major redn. in non-radiative voltage losses at a very small ΔEHOMO. Ultimately, highly luminescent near-IR emitters with very long exciton lifetimes are suggested to enable highly efficient org. solar cells.
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161Melikov, R.; Srivastava, S. B.; Karatum, O.; Dogru-Yuksel, I. B.; Bahmani Jalali, H.; Sadeghi, S.; Dikbas, U. M.; Ulgut, B.; Kavakli, I. H.; Cetin, A. E.; Nizamoglu, S. Plasmon-Coupled Photocapacitor Neuromodulators. ACS Appl. Mater. Interfaces 2020, 12 (32), 35940– 35949, DOI: 10.1021/acsami.0c09455Google Scholar161https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtl2rs7vJ&md5=dfca3d90ace51d08ca8bbec90a9827f3Plasmon-Coupled Photocapacitor NeuromodulatorsMelikov, Rustamzhon; Srivastava, Shashi Bhushan; Karatum, Onuralp; Dogru-Yuksel, Itir Bakis; Bahmani Jalali, Houman; Sadeghi, Sadra; Dikbas, Ugur Meric; Ulgut, Burak; Kavakli, Ibrahim Halil; Cetin, Arif E.; Nizamoglu, SedatACS Applied Materials & Interfaces (2020), 12 (32), 35940-35949CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Efficient transduction of optical energy to bioelec. stimuli is an important goal for effective communication with biol. systems. For that, plasmonics has a significant potential via boosting the light-matter interactions. However, plasmonics has been primarily used for heat-induced cell stimulation due to membrane capacitance change (i.e., optocapacitance). Instead, here, we demonstrate that plasmonic coupling to photocapacitor biointerfaces improves safe and efficacious neuromodulating displacement charges for an av. of 185% in the entire visible spectrum while maintaining the faradic currents below 1%. Hot-electron injection dominantly leads the enhancement of displacement current in the blue spectral window, and the nanoantenna effect is mainly responsible for the improvement in the red spectral region. The plasmonic photocapacitor facilitates wireless modulation of single cells at three orders of magnitude below the max. retinal intensity levels, corresponding to one of the most sensitive optoelectronic neural interfaces. This study introduces a new way of using plasmonics for safe and effective photostimulation of neurons and paves the way toward ultrasensitive plasmon-assisted neurostimulation devices.
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162Kesim, C.; Han, M.; Yildiz, E.; Bahmani Jalali, H.; Qureshi, M. H.; Hasanreisoglu, M.; Nizamoglu, S.; Sahin, A. Biocompatibility and Neural Stimulation Capacity of Aluminum Antimonide Nanocrystals Biointerfaces for Use in Artificial Vision. Invest. Ophthalmol. Vis. Sci. 2021, 62 (8), 3217Google ScholarThere is no corresponding record for this reference.
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163Jaiswal, J. K.; Mattoussi, H.; Mauro, J. M.; Simon, S. M. Long-Term Multiple Color Imaging of Live Cells Using Quantum Dot Bioconjugates. Nat. Biotechnol. 2003, 21 (1), 47– 51, DOI: 10.1038/nbt767Google Scholar163https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhvVyq&md5=fa97be979d4d5fae784e7239cb6a164eLong-term multiple color imaging of live cells using quantum dot bioconjugatesJaiswal, Jyoti K.; Mattoussi, Hedi; Mauro, J. Matthew; Simon, Sanford M.Nature Biotechnology (2003), 21 (1), 47-51CODEN: NABIF9; ISSN:1087-0156. (Nature Publishing Group)Luminescent quantum dots (QDs)-semiconductor nanocrystals-are a promising alternative to org. dyes for fluorescence-based applications. We have developed procedures for using QDs to label live cells and have demonstrated their use for long-term multicolor imaging of live cells. The two approaches presented are (i) endocytic uptake of QDs and (ii) selective labeling of cell surface proteins with QDs conjugated to antibodies. Live cells labeled using these approaches were used for long-term multicolor imaging. The cells remained stably labeled for over a week as they grew and developed. These approaches should permit the simultaneous study of multiple cells over long periods of time as they proceed through growth and development.
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164Derfus, A. M.; Chan, W. C. W.; Bhatia, S. N. Probing the Cytotoxicity of Semiconductor Quantum Dots. Nano Lett. 2004, 4 (1), 11– 18, DOI: 10.1021/nl0347334Google Scholar164https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXps1SmtLo%253D&md5=c5953773f4169b5256f0fdb7d53fee08Probing the Cytotoxicity of Semiconductor Quantum DotsDerfus, Austin M.; Chan, Warren C. W.; Bhatia, Sangeeta N.Nano Letters (2004), 4 (1), 11-18CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)With their bright, photostable fluorescence, semiconductor quantum dots (QDs) show promise as alternatives to org. dyes for biol. labeling. Questions about their potential cytotoxicity, however, remain unanswered. While cytotoxicity of bulk cadmium selenide (CdSe) is well documented, a no. of groups have suggested that CdSe QDs are cytocompatible, at least with some immortalized cell lines. Using primary hepatocytes as a liver model, we found that CdSe-core QDs were indeed acutely toxic under certain conditions. Specifically, we found that the cytotoxicity of QDs was modulated by processing parameters during synthesis, exposure to UV light, and surface coatings. Our data further suggest that cytotoxicity correlates with the liberation of free Cd2+ ions due to deterioration of the CdSe lattice. When appropriately coated, CdSe-core QDs can be rendered nontoxic and used to track cell migration and reorganization in vitro. Our results provide information for design criteria for the use of QDs in vitro and esp. in vivo, where deterioration over time may occur.
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165Rosenthal, S. J.; Chang, J. C.; Kovtun, O.; McBride, J. R.; Tomlinson, I. D. Biocompatible Quantum Dots for Biological Applications. Chem. Biol. 2011, 18 (1), 10– 24, DOI: 10.1016/j.chembiol.2010.11.013Google Scholar165https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlaku7Y%253D&md5=665dbadc6d8f33b993e285bed85586a8Biocompatible Quantum Dots for Biological ApplicationsRosenthal, Sandra J.; Chang, Jerry C.; Kovtun, Oleg; McBride, James R.; Tomlinson, Ian D.Chemistry & Biology (Cambridge, MA, United States) (2011), 18 (1), 10-24CODEN: CBOLE2; ISSN:1074-5521. (Cell Press)A review. Semiconductor quantum dots are quickly becoming a crit. diagnostic tool for discerning cellular function at the mol. level. Their high brightness, long-lasting, size-tunable, and narrow luminescence set them apart from conventional fluorescence dyes. Quantum dots are being developed for a variety of biol. oriented applications, including fluorescent assays for drug discovery, disease detection, single protein tracking, and intracellular reporting. This review introduces the science behind quantum dots and describes how they are made biol. compatible. Several applications are also included, illustrating strategies toward target specificity, and are followed by a discussion on the limitations of quantum dot approaches. The article is concluded with a look at the future direction of quantum dots.
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166Gao, X.; Chan, W. C. W.; Nie, S. Quantum-Dot Nanocrystals for Ultrasensitive Biological Labeling and Multicolor Optical Encoding. J. Biomed. Opt. 2002, 7 (4), 532, DOI: 10.1117/1.1506706Google Scholar166https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XotFyqsLk%253D&md5=222984987fb11bc8e4926feb27571243Quantum-dot nanocrystals for ultrasensitive biological labeling and multicolor optical encodingGao, Xiaohu; Chan, Warren C. W.; Nie, ShumingJournal of Biomedical Optics (2002), 7 (4), 532-537CODEN: JBOPFO; ISSN:1083-3668. (SPIE-The International Society for Optical Engineering)Semiconductor nanoparticles in the size range of 2-6 nm are of great current interest, not only because of their size-tunable properties but also because of their dimensional similarity with biol. macromols. (e.g., nucleic acids and proteins). This similarity could allow an integration of nanomaterials with biol. mols., which would have applications in medical diagnostics, targeted therapeutics, and high-throughput drug screening. Here we report new developments in prepg. highly luminescent and biocompatible CdSe quantum dots (QDs), and in synthesizing QD-encoded micro- and nano-beads in the size range of 100 nm-10 μm. We show that the optical properties of ZnS-capped CdSe quantum dots are sensitive to environmental factors such as pH and divalent cations, leading to the potential use of quantum dots in mol. sensing. We also show that chem. modified proteins can be used to coat the surface of water-sol. QDs, to restore their fluorescence, and to provide functional groups for bioconjugation. For multiplexed optical encoding, we have prepd. large microbeads with sizes similar to that of mammalian cells, and small nanobeads with sizes similar to that of viruses.
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167Devatha, G.; Roy, S.; Rao, A.; Mallick, A.; Basu, S.; Pillai, P. P. Electrostatically Driven Resonance Energy Transfer in “Cationic” Biocompatible Indium Phosphide Quantum Dots. Chem. Sci. 2017, 8 (5), 3879– 3884, DOI: 10.1039/C7SC00592JGoogle Scholar167https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXktFykur8%253D&md5=4258e94b7eb9012b952b3e7c6aab42d8Electrostatically driven resonance energy transfer in "cationic" biocompatible indium phosphide quantum dotsDevatha, Gayathri; Roy, Soumendu; Rao, Anish; Mallick, Abhik; Basu, Sudipta; Pillai, Pramod P.Chemical Science (2017), 8 (5), 3879-3884CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)Indium Phosphide Quantum Dots (InP QDs) have emerged as an alternative to toxic metal ion based QDs in nanobiotechnol. The ability to generate cationic surface charge, without compromising stability and biocompatibility, is essential in realizing the full potential of InP QDs in biol. applications. We have addressed this challenge by developing a place exchange protocol for the prepn. of cationic InP/ZnS QDs. The quaternary ammonium group provides the much required permanent pos. charge and stability to InP/ZnS QDs in biofluids. The two important properties of QDs, namely bioimaging and light induced resonance energy transfer, are successfully demonstrated in cationic InP/ZnS QDs. The low cytotoxicity and stable photoluminescence of cationic InP/ZnS QDs inside cells make them ideal candidates as optical probes for cellular imaging. An efficient resonance energy transfer (E ∼ 60%) is obsd., under physiol. conditions, between the cationic InP/ZnS QD donor and anionic dye acceptor. A large bimol. quenching const. along with a linear Stern-Volmer plot confirms the formation of a strong ground state complex between the cationic InP/ZnS QDs and the anionic dye. Control expts. prove the role of electrostatic attraction in driving the light induced interactions, which can rightfully form the basis for future nano-bio studies between cationic InP/ZnS QDs and anionic biomols.
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168Chen, L.-D.; Liu, J.; Yu, X.-F.; He, M.; Pei, X.-F.; Tang, Z.-Y.; Wang, Q.-Q.; Pang, D.-W.; Li, Y. The Biocompatibility of Quantum Dot Probes Used for the Targeted Imaging of Hepatocellular Carcinoma Metastasis. Biomaterials 2008, 29 (31), 4170– 4176, DOI: 10.1016/j.biomaterials.2008.07.025Google Scholar168https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVaju7jL&md5=619d04d17ac0436a69941cd93a1c5577The biocompatibility of quantum dot probes used for the targeted imaging of hepatocellular carcinoma metastasisChen, Liang-Dong; Liu, Jia; Yu, Xue-Feng; He, Man; Pei, Xiao-Feng; Tang, Zhao-You; Wang, Qu-Quan; Pang, Dai-Wen; Li, YanBiomaterials (2008), 29 (31), 4170-4176CODEN: BIMADU; ISSN:0142-9612. (Elsevier Ltd.)Semiconductor quantum dots (QDs) have several photo-phys. advantages over org. dyes making them good markers in biomedical application. We used CdSe/ZnS QDs with max. emission wavelength of 590 nm (QD590) linked to alpha-fetoprotein (AFP) monoclonal antibody (Ab) to detect AFP in cytoplasm of human hepatocellular carcinoma (HCC) cell line HCCLM6. For the in vivo studies, we used QD-AFP-Ab probes for targeted imaging of human HCC xenograft growing in nude mice by injecting them into the tail vein. In addn., the cytotoxicity in vitro, the acute toxicity in vivo, the hemodynamics and tissue distribution of these probes were also investigated. The results in vitro and in vivo indicate that our QD-based probes have good stability, specificity and biocompatibility for ultrasensitive fluorescence imaging of mol. targets in our liver cancer model system.
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169Cogan, S. F.; Ludwig, K. A.; Welle, C. G.; Takmakov, P. Tissue Damage Thresholds during Therapeutic Electrical Stimulation. J. Neural Eng. 2016, 13 (2), 021001, DOI: 10.1088/1741-2560/13/2/021001Google Scholar169https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28nivVSltw%253D%253D&md5=8804003dcd9fca783a975b2c6f87c220Tissue damage thresholds during therapeutic electrical stimulationCogan Stuart F; Ludwig Kip A; Welle Cristin G; Takmakov PavelJournal of neural engineering (2016), 13 (2), 021001 ISSN:.OBJECTIVE: Recent initiatives in bioelectronic modulation of the nervous system by the NIH (SPARC), DARPA (ElectRx, SUBNETS) and the GlaxoSmithKline Bioelectronic Medicines effort are ushering in a new era of therapeutic electrical stimulation. These novel therapies are prompting a re-evaluation of established electrical thresholds for stimulation-induced tissue damage. APPROACH: In this review, we explore what is known and unknown in published literature regarding tissue damage from electrical stimulation. MAIN RESULTS: For macroelectrodes, the potential for tissue damage is often assessed by comparing the intensity of stimulation, characterized by the charge density and charge per phase of a stimulus pulse, with a damage threshold identified through histological evidence from in vivo experiments as described by the Shannon equation. While the Shannon equation has proved useful in assessing the likely occurrence of tissue damage, the analysis is limited by the experimental parameters of the original studies. Tissue damage is influenced by factors not explicitly incorporated into the Shannon equation, including pulse frequency, duty cycle, current density, and electrode size. Microelectrodes in particular do not follow the charge per phase and charge density co-dependence reflected in the Shannon equation. The relevance of these factors to tissue damage is framed in the context of available reports from modeling and in vivo studies. SIGNIFICANCE: It is apparent that emerging applications, especially with microelectrodes, will require clinical charge densities that exceed traditional damage thresholds. Experimental data show that stimulation at higher charge densities can be achieved without causing tissue damage, suggesting that safety parameters for microelectrodes might be distinct from those defined for macroelectrodes. However, these increased charge densities may need to be justified by bench, non-clinical or clinical testing to provide evidence of device safety.
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170Brocker, D. T.; Grill, W. M. Principles of Electrical Stimulation of Neural Tissue. In Handbook of Clinical Neurology; Lozano, A. M., Hallett, M., Eds.; Elsevier, 2013; Vol. 116, pp 3– 18. DOI: 10.1016/B978-0-444-53497-2.00001-2Google ScholarThere is no corresponding record for this reference.
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171Rizzo III, J. F.; Wyatt, J.; Loewenstein, J.; Kelly, S.; Shire, D. Methods and Perceptual Thresholds for Short-Term Electrical Stimulation of Human Retina with Microelectrode Arrays. Invest. Ophthalmol. Vis. Sci. 2003, 44 (12), 5355– 5361, DOI: 10.1167/iovs.02-0819Google ScholarThere is no corresponding record for this reference.
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172Butterwick, A. F.; Vankov, A.; Huie, P.; Palanker, D. V. Dynamic Range of Safe Electrical Stimulation of the Retina. Ophthalmic Technologies XVI 2006, 6138, 61380Q, DOI: 10.1117/12.650652Google ScholarThere is no corresponding record for this reference.
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173Zhang, J.; Tang, Y.; Lee, K.; Ouyang, M. Nonepitaxial Growth of Hybrid Core-Shell Nanostructures with Large Lattice Mismatches. Science (80-.). 2010, 327 (5973), 1634– 1638, DOI: 10.1126/science.1184769Google ScholarThere is no corresponding record for this reference.
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174Sadeghi, S.; Melikov, R.; Sahin, M.; Nizamoglu, S. Cation Exchange Mediated Synthesis of Bright Au@ZnTe Core-Shell Nanocrystals. Nanotechnology 2021, 32 (2), 025603, DOI: 10.1088/1361-6528/abbb02Google Scholar174https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXit1KmurrJ&md5=7181405fb2dda23386105b45d96db3f1Cation exchange mediated synthesis of bright Au@ZnTe core-shell nanocrystalsSadeghi, Sadra; Melikov, Rustamzhon; Sahin, Mehmet; Nizamoglu, SedatNanotechnology (2021), 32 (2), 025603CODEN: NNOTER; ISSN:1361-6528. (IOP Publishing Ltd.)The synthesis of heterostructured core-shell nanocrystals has attracted significant attention due to their wide range of applications in energy, medicine and environment. To further extend the possible nanostructures, non-epitaxial growth is introduced to form heterostructures with large lattice mismatches, which cannot be achieved by classical epitaxial growth techniques. Here, we report the synthetic procedure of Au@ZnTe core-shell nanostructures by cation exchange reaction for the first time. For that, bimetallic Au@Ag heterostructures were synthesized by using PDDA as stabilizer and shape-controller. Then, by addn. of Te and Zn precursors in a step-wise reaction, the zinc and silver cation exchange was performed and Au@ZnTe nanocrystals were obtained. Structural and optical characterization confirmed the formation of the Au@ZnTe nanocrystals. The optimization of the synthesis led to the bright nanocrystals with a photoluminescence quantum yield up to 27%. The non-toxic, versatile synthetic route, and bright emission of the synthesized Au@ZnTe nanocrystals offer significant potential for future bio-imaging and optoelectronic applications.
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175Zhang, Y.; Zhu, X.; Zhang, Y. Exploring Heterostructured Upconversion Nanoparticles: From Rational Engineering to Diverse Applications. ACS Nano 2021, 15 (3), 3709– 3735, DOI: 10.1021/acsnano.0c09231Google Scholar175https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXlvVKktbo%253D&md5=95749020a6713f3147a568c73dd92923Exploring Heterostructured Upconversion Nanoparticles: From Rational Engineering to Diverse ApplicationsZhang, Yi; Zhu, Xiaohui; Zhang, YongACS Nano (2021), 15 (3), 3709-3735CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. Upconversion nanoparticles (UCNPs) represent a class of optical nanomaterials that can convert low-energy excitation photons to high-energy fluorescence emissions. From UCNPs, heterostructured UCNPs, consisting of UCNPs and other functional counterparts (metals, semiconductors, polymers, etc.), present an intriguing system in which the physicochem. properties are largely influenced by the entire assembled particle and also by the morphol., dimension, and compn. of each individual component. As multicomponent nanomaterials, heterostructured UCNPs can overcome challenges assocd. with a single component and exhibit bifunctional or multifunctional properties, which can further expand their applications in bioimaging, biodetection, and phototherapy. In this review, the authors provide a summary of recent achievements in the field of heterostructured UCNPs in the aspects of construction strategies, synthetic approaches, and types of heterostructured UCNPs. This review also summarizes the trends in biomedical applications of heterostructured UCNPs and discusses the challenges and potential solns. in this field.
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176Wu, X.; Zhang, Y.; Takle, K.; Bilsel, O.; Li, Z.; Lee, H.; Zhang, Z.; Li, D.; Fan, W.; Duan, C.; Chan, E. M.; Lois, C.; Xiang, Y.; Han, G. Dye-Sensitized Core/Active Shell Upconversion Nanoparticles for Optogenetics and Bioimaging Applications. ACS Nano 2016, 10 (1), 1060– 1066, DOI: 10.1021/acsnano.5b06383Google Scholar176https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XjvFeisg%253D%253D&md5=3d945e6f3ca91b8d8d9ed96d0b825b9cDye-Sensitized Core/Active Shell Upconversion Nanoparticles for Optogenetics and Bioimaging ApplicationsWu, Xiang; Zhang, Yuanwei; Takle, Kendra; Bilsel, Osman; Li, Zhanjun; Lee, Hyungseok; Zhang, Zijiao; Li, Dongsheng; Fan, Wei; Duan, Chunying; Chan, Emory M.; Lois, Carlos; Xiang, Yang; Han, GangACS Nano (2016), 10 (1), 1060-1066CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Near-IR (NIR) dye-sensitized upconversion nanoparticles (UCNPs) can broaden the absorption range and boost upconversion efficiency of UCNPs. Here, we achieved significantly enhanced upconversion luminescence in dye-sensitized core/active shell UCNPs via the doping of ytterbium ions (Yb3+) in the UCNP shell, which bridged the energy transfer from the dye to the UCNP core. As a result, we synergized the two most practical upconversion booster effectors (dye-sensitizing and core/shell enhancement) to amplify upconversion efficiency. We demonstrated two biomedical applications using these UCNPs. By using dye-sensitized core/active shell UCNP embedded poly(Me methacrylate) polymer implantable systems, we successfully shifted the optogenetic neuron excitation window to a biocompatible and deep tissue penetrable 800 nm wavelength. Furthermore, UCNPs were water-solubilized with Pluronic F127 with high upconversion efficiency and can be imaged in a mouse model.
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177Lin, X.; Chen, X.; Zhang, W.; Sun, T.; Fang, P.; Liao, Q.; Chen, X.; He, J.; Liu, M.; Wang, F.; Shi, P. Core-Shell-Shell Upconversion Nanoparticles with Enhanced Emission for Wireless Optogenetic Inhibition. Nano Lett. 2018, 18 (2), 948– 956, DOI: 10.1021/acs.nanolett.7b04339Google Scholar177https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXitVeltL7L&md5=275e099037653df567929d4fdf9c107eCore-Shell-Shell Upconversion Nanoparticles with Enhanced Emission for Wireless Optogenetic InhibitionLin, Xudong; Chen, Xian; Zhang, Wenchong; Sun, Tianying; Fang, Peilin; Liao, Qinghai; Chen, Xi; He, Jufang; Liu, Ming; Wang, Feng; Shi, PengNano Letters (2018), 18 (2), 948-956CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Recent advances in upconversion technol. have enabled optogenetic neural stimulation using remotely applied optical signals, but limited success was demonstrated for neural inhibition by using this method, primarily due to the much higher optical power and more red-shifted excitation spectrum that are required to work with the appropriate inhibitory opsin proteins. To overcome these limitations, core-shell-shell upconversion nanoparticles (UCNPs) with a hexagonal phase are synthesized to optimize the doping contents of Yb3+ and to mitigate Yb-assocd. concn. quenching. Such UCNPs' emission contains an almost 3-fold enhanced peak around 540-570 nm, matching the excitation spectrum of a commonly used inhibitory opsin protein, halorhodopsin. The enhanced UCNPs are used as optical transducers to develop a fully implantable upconversion-based device for in vivo tetherless optogenetic inhibition, which is actuated by near-IR (NIR) light irradn. without any electronics. When the device is implanted into targeted sites deep in the rat brain, the elec. activity of the neurons is reliably inhibited with NIR irradn. and restores to normal level upon switching off the NIR light. The system is further used to perform tetherless unilateral inhibition of the secondary motor cortex in behaving mice, achieving control of their motor functions. This study provides an important and useful supplement to the upconversion-based optogenetic toolset, which is beneficial for both basic and translational neuroscience studies.
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178Yu, N.; Huang, L.; Zhou, Y.; Xue, T.; Chen, Z.; Han, G. Near-Infrared-Light Activatable Nanoparticles for Deep-Tissue-Penetrating Wireless Optogenetics. Adv. Healthc. Mater. 2019, 8 (6), 1801132, DOI: 10.1002/adhm.201801132Google ScholarThere is no corresponding record for this reference.
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179Chen, S.; Weitemier, A. Z.; Zeng, X.; He, L.; Wang, X.; Tao, Y.; Huang, A. J. Y.; Hashimotodani, Y.; Kano, M.; Iwasaki, H. Near-Infrared Deep Brain Stimulation via Upconversion Nanoparticle-Mediated Optogenetics. Science 2018, 359 (6376), 679– 684, DOI: 10.1126/science.aaq1144Google Scholar179https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1CjtLk%253D&md5=c2f1bffdd2bff528c7df816fd9811a1eNear-infrared deep brain stimulation via upconversion nanoparticle-mediated optogeneticsChen, Shuo; Weitemier, Adam Z.; Zeng, Xiao; He, Linmeng; Wang, Xiyu; Tao, Yanqiu; Huang, Arthur J. Y.; Hashimotodani, Yuki; Kano, Masanobu; Iwasaki, Hirohide; Parajuli, Laxmi Kumar; Okabe, Shigeo; Teh, Daniel B. Loong; All, Angelo H.; Tsutsui-Kimura, Iku; Tanaka, Kenji F.; Liu, Xiaogang; McHugh, Thomas J.Science (Washington, DC, United States) (2018), 359 (6376), 679-684CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Optogenetics has revolutionized the exptl. interrogation of neural circuits and holds promise for the treatment of neurol. disorders. It is limited, however, because visible light cannot penetrate deep inside brain tissue. Upconversion nanoparticles (UCNPs) absorb tissue-penetrating near-IR (NIR) light and emit wavelength-specific visible light. Here, we demonstrate that molecularly tailored UCNPs can serve as optogenetic actuators of transcranial NIR light to stimulate deep brain neurons. Transcranial NIR UCNP-mediated optogenetics evoked dopamine release from genetically tagged neurons in the ventral tegmental area, induced brain oscillations through activation of inhibitory neurons in the medial septum, silenced seizure by inhibition of hippocampal excitatory cells, and triggered memory recall. UCNP technol. will enable less-invasive optical neuronal activity manipulation with the potential for remote therapy.
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180All, A. H.; Zeng, X.; Teh, D. B. L.; Yi, Z.; Prasad, A.; Ishizuka, T.; Thakor, N.; Hiromu, Y.; Liu, X. Expanding the Toolbox of Upconversion Nanoparticles for In Vivo Optogenetics and Neuromodulation. Adv. Mater. 2019, 31 (41), 1803474, DOI: 10.1002/adma.201803474Google Scholar180https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1aitr3F&md5=97761b5e5e7c660e387f7e823607df58Expanding the Toolbox of Upconversion Nanoparticles for In Vivo Optogenetics and NeuromodulationAll, Angelo Homayoun; Zeng, Xiao; Teh, Daniel Boon Loong; Yi, Zhigao; Prasad, Ankshita; Ishizuka, Toru; Thakor, Nitish; Hiromu, Yawo; Liu, XiaogangAdvanced Materials (Weinheim, Germany) (2019), 31 (41), 1803474CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Optogenetics is an optical technique that exploits visible light for selective neuromodulation with spatio-temporal precision. Despite enormous effort, the effective stimulation of targeted neurons, which are located in deeper structures of the nervous system, by visible light, remains a tech. challenge. Compared to visible light, near-IR illumination offers a higher depth of tissue penetration owing to a lower degree of light attenuation. Herein, an overview of advances in developing new modalities for neural circuitry modulation utilizing upconversion-nanoparticle-mediated optogenetics is presented. These developments have led to minimally invasive optical stimulation and inhibition of neurons with substantially improved selectivity, sensitivity, and spatial resoln. The focus is to provide a comprehensive review of the mechanistic basis for evaluating upconversion parameters, which will be useful in designing, executing, and reporting optogenetic expts.
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181Shao, B.; Yang, Z.; Wang, Y.; Li, J.; Yang, J.; Qiu, J.; Song, Z. Coupling of Ag Nanoparticle with Inverse Opal Photonic Crystals as a Novel Strategy for Upconversion Emission Enhancement of NaYF4: Yb3+, Er3+ Nanoparticles. ACS Appl. Mater. Interfaces 2015, 7 (45), 25211– 25218, DOI: 10.1021/acsami.5b06817Google Scholar181https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhslSlsbnL&md5=1d2d9a8f3573618e344bc6d839f11c2bCoupling of Ag Nanoparticle with Inverse Opal Photonic Crystals as a Novel Strategy for Upconversion Emission Enhancement of NaYF4:Yb3+,Er3+ NanoparticlesShao, Bo; Yang, Zhengwen; Wang, Yida; Li, Jun; Yang, Jianzhi; Qiu, Jianbei; Song, ZhiguoACS Applied Materials & Interfaces (2015), 7 (45), 25211-25218CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Rare-earth-ion-doped upconversion (UC) nanoparticles have generated considerable interest because of their potential application in solar cells, biol. labeling, therapeutics, and imaging. However, the applications of UC nanoparticles were still limited because of their low emission efficiency. Photonic crystals and noble metal nanoparticles are applied extensively to enhance the UC emission of rare earth ions. A novel substrate consisting of inverse opal photonic crystals and Ag nanoparticles was prepd. by the template-assisted method, which was used to enhance the UC emission of NaYF4: Yb3+, Er3+ nanoparticles. The red or green UC emissions of NaYF4: Yb3+, Er3+ nanoparticles were selectively enhanced on the inverse opal substrates because of the Bragg reflection of the photonic band gap. Addnl., the UC emission enhancement of NaYF4: Yb3+, Er3+ nanoparticles induced by the coupling of metal nanoparticle plasmons and photonic crystal effects was realized on the Ag nanoparticles included in the inverse opal substrate. Coupling of Ag nanoparticle with inverse opal photonic crystals provides a useful strategy to enhance UC emission of rare-earth-ion-doped nanoparticles.
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182Chu, C.-Y.; Wu, P.-W.; Chen, J.-C.; Tsou, N.-T.; Lin, Y.-Y.; Lo, Y.-C.; Li, S.-J.; Chang, C.-W.; Chen, B.-W.; Tsai, C.-L. Flexible Optogenetic Transducer Device for Remote Neuron Modulation Using Highly Upconversion Efficient Dendrite-like Gold Inverse Opaline Structure. Adv. Healthc. Mater. 2022, 2101310, DOI: 10.1002/adhm.202101310Google ScholarThere is no corresponding record for this reference.
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183Ahn, H.; Kim, S.; Kim, Y.; Kim, S.; Choi, J.; Kim, K. Plasmonic Sensing, Imaging, and Stimulation Techniques for Neuron Studies. Biosens. Bioelectron. 2021, 182, 113150, DOI: 10.1016/j.bios.2021.113150Google Scholar183https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXns1ehtLg%253D&md5=e2e2351e57925c82d84ed839267b7817Plasmonic sensing, imaging, and stimulation techniques for neuron studiesAhn, Heesang; Kim, Soojung; Kim, Yoonhee; Kim, Seungchul; Choi, Jong-ryul; Kim, KyujungBiosensors & Bioelectronics (2021), 182 (), 113150CODEN: BBIOE4; ISSN:0956-5663. (Elsevier B.V.)Studies to understand the structure, functions, and electrophysiol. properties of neurons have been conducted at the frontmost end of neuroscience. Such studies have led to the active development of high-performance research tools for exploring the neurobiol. at the cellular and mol. level. Following this trend, research and application of plasmonics, which is a technol. employed in high-sensitivity optical biosensors and high-resoln. imaging, is essential for studying neurons, as plasmonic nanoprobes can be used to stimulate specific areas of cells. In this study, three plasmonic modalities were explored as tools to study neurons and their responses: (1) plasmonic sensing of neuronal activities and neuron-related chems.; (2) performance-improved optical imaging of neurons using plasmonic enhancements; and (3) plasmonic neuromodulations. Through a detailed investigation of these plasmonic modalities and research subjects that can be combined with them, it was confirmed that plasmonic sensing, imaging, and stimulation techniques have the potential to be effectively employed for the study of neurons and understanding their specific mol. activities.
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184Bruno, G.; Melle, G.; Barbaglia, A.; Iachetta, G.; Melikov, R.; Perrone, M.; Dipalo, M.; De Angelis, F. All-Optical and Label-Free Stimulation of Action Potentials in Neurons and Cardiomyocytes by Plasmonic Porous Metamaterials. Adv. Sci. 2021, 8 (21), 2100627, DOI: 10.1002/advs.202100627Google Scholar184https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XjtVSru7c%253D&md5=417a8d4e2b497c33a936e854a7bdfddfAll-Optical and Label-Free Stimulation of Action Potentials in Neurons and Cardiomyocytes by Plasmonic Porous MetamaterialsBruno, Giulia; Melle, Giovanni; Barbaglia, Andrea; Iachetta, Giuseppina; Melikov, Rustamzhon; Perrone, Michela; Dipalo, Michele; De Angelis, FrancescoAdvanced Science (Weinheim, Germany) (2021), 8 (21), 2100627CODEN: ASDCCF; ISSN:2198-3844. (Wiley-VCH Verlag GmbH & Co. KGaA)Optical stimulation technologies are gaining great consideration in cardiol., neuroscience studies, and drug discovery pathways by providing control over cell activity with high spatio-temporal resoln. However, this high precision requires manipulation of biol. processes at genetic level concealing its development from broad scale application. Therefore, translating these technologies into tools for medical or pharmacol. applications remains a challenge. Here, an all-optical nongenetic method for the modulation of electrogenic cells is introduced. It is demonstrated that plasmonic metamaterials can be used to elicit action potentials by converting near IR laser pulses into stimulatory currents. The suggested approach allows for the stimulation of cardiomyocytes and neurons directly on com. complementary metal-oxide semiconductor microelectrode arrays coupled with ultrafast pulsed laser, providing both stimulation and network-level recordings on the same device.
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185Parameswaran, R.; Koehler, K.; Rotenberg, M. Y.; Burke, M. J.; Kim, J.; Jeong, K. Y.; Hissa, B.; Paul, M. D.; Moreno, K.; Sarma, N.; Hayes, T.; Sudzilovsky, E.; Park, H. G.; Tian, B. Optical Stimulation of Cardiac Cells with a Polymer-Supported Silicon Nanowire Matrix. Proc. Natl. Acad. Sci. U. S. A. 2019, 116 (2), 413– 421, DOI: 10.1073/pnas.1816428115Google Scholar185https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXlvVKltw%253D%253D&md5=2ecb717871943c39819259edfc89f675Optical stimulation of cardiac cells with a polymer-supported silicon nanowire matrixParameswaran, Ramya; Koehler, Kelliann; Rotenberg, Menahem Y.; Burke, Michael J.; Kim, Jungkil; Jeong, Kwang-Yong; Hissa, Barbara; Paul, Michael D.; Moreno, Kiela; Sarma, Nivedina; Hayes, Thomas; Sudzilovsky, Edward; Park, Hong-Gyu; Tian, BozhiProceedings of the National Academy of Sciences of the United States of America (2019), 116 (2), 413-421CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Electronic pacemakers can treat elec. conduction disorders in hearts; however, they are invasive, bulky, and linked to increased incidence of infection at the tissue-device interface. Thus, researchers have looked to other more biocompatible methods for cardiac pacing or resynchronization, such as femtosecond IR light pulsing, optogenetics, and polymer-based cardiac patches integrated with metal electrodes. Here the authors develop a biocompatible nongenetic approach for the optical modulation of cardiac cells and tissues. A polymer-silicon nanowire composite mesh can be used to convert fast moving, low-radiance optical inputs into stimulatory signals in target cardiac cells. The authors' method allows for the stimulation of the cultured cardiomyocytes or ex vivo heart to beat at a higher target frequency.
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186Jiang, Y.; Li, X.; Liu, B.; Yi, J.; Fang, Y.; Shi, F.; Gao, X.; Sudzilovsky, E.; Parameswaran, R.; Koehler, K.; Nair, V.; Yue, J.; Guo, K. H.; Fang, Y.; Tsai, H. M.; Freyermuth, G.; Wong, R. C. S.; Kao, C. M.; Chen, C. T.; Nicholls, A. W.; Wu, X.; Shepherd, G. M. G.; Tian, B. Rational Design of Silicon Structures for Optically Controlled Multiscale Biointerfaces. Nat. Biomed. Eng. 2018, 2 (7), 508– 521, DOI: 10.1038/s41551-018-0230-1Google Scholar186https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtFensrzO&md5=f13d567e5edd81f3e42c2d75ec1af79cRational design of silicon structures for optically controlled multiscale biointerfacesJiang, Yuanwen; Li, Xiaojian; Liu, Bing; Yi, Jaeseok; Fang, Yin; Shi, Fengyuan; Gao, Xiang; Sudzilovsky, Edward; Parameswaran, Ramya; Koehler, Kelliann; Nair, Vishnu; Yue, Jiping; Guo, KuangHua; Tsai, Hsiu-Ming; Freyermuth, George; Wong, Raymond C. S.; Kao, Chien-Min; Chen, Chin-Tu; Nicholls, Alan W.; Wu, Xiaoyang; Shepherd, Gordon M. G.; Tian, BozhiNature Biomedical Engineering (2018), 2 (7), 508-521CODEN: NBEAB3; ISSN:2157-846X. (Nature Research)Silicon-based materials have been widely used in biol. applications. However, remotely controlled and interconnect-free silicon configurations have been rarely explored, because of limited fundamental understanding of the complex physicochem. processes that occur at interfaces between silicon and biol. materials. Here, we describe rational design principles, guided by biol., for establishing intracellular, intercellular and extracellular silicon-based interfaces, where the silicon and the biol. targets have matched properties. We focused on light-induced processes at these interfaces, and developed a set of matrixes to quantify and differentiate the capacitive, Faradaic and thermal outputs from about 30 different silicon materials in saline. We show that these interfaces are useful for the light-controlled non-genetic modulation of intracellular calcium dynamics, of cytoskeletal structures and transport, of cellular excitability, of neurotransmitter release from brain slices and of brain activity in vivo.
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187Dogru-Yuksel, I. B.; Han, M.; Pirnat, G.; Magden, E. S.; Senses, E.; Humar, M.; Nizamoglu, S. High-Q, Directional and Self-Assembled Random Laser Emission Using Spatially Localized Feedback via Cracks. APL Photonics 2020, 5 (10), 106105, DOI: 10.1063/5.0020528Google Scholar187https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXotFWgt7c%253D&md5=857fc45bcfd3170607012509e4007b76High-Q, directional and self-assembled random laser emission using spatially localized feedback via cracksDogru-Yuksel, Itir Bakis; Han, Mertcan; Pirnat, Gregor; Magden, Emir Salih; Senses, Erkan; Humar, Matjaz; Nizamoglu, SedatAPL Photonics (2020), 5 (10), 106105CODEN: APPHD2; ISSN:2378-0967. (American Institute of Physics)Lasers based on Fabry-Perot or whispering gallery resonators generally require complex fabrication stages and sensitive alignment of cavity configurations. The structural defects on reflective surfaces result in scattering and induce optical losses that can be detrimental to laser performance. On the other hand, random lasers can be simply obtained by forming disordered gain media and scatterers, but they generally show omnidirectional emission with a low Q-factor. Here, we demonstrate directional random lasers with a high Q-factor emission (∼1.5 x 104) via self-assembled microstructural cracks that are spontaneously formed upon radial strain-release of colloidal nanoparticles from the wet to dry phase. The rough sidewalls of cracks facilitate light oscillation via diffuse reflection that forms a spatially localized feedback, and they also serve as the laser out-coupler. These self-assembled cracks exhibit random lasing at optical pump powers as low as tens of μJ/mm2. We demonstrate a wide variety of random lasers from nano- and biomaterials including silica nanoparticles, fluorescent proteins, and biopolymers. These findings pave the way toward self-assembled, configurable, and scalable random lasers for sensing, displays, and communication applications. (c) 2020 American Institute of Physics.
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188Wang, L.; Zhao, W.; Tan, W. Bioconjugated Silica Nanoparticles: Development and Applications. Nano Res. 2008, 1 (2), 99– 115, DOI: 10.1007/s12274-008-8018-3Google Scholar188https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVymtLzL&md5=86ea65f84ba4dfe98d78b20b2ab5b225Bioconjugated silica nanoparticles: development and applicationsWang, Lin; Zhao, Wenjun; Tan, WeihongNano Research (2008), 1 (2), 99-115CODEN: NRAEB5; ISSN:1998-0124. (Springer)A review. Advanced bioanal., including accurate quantitation, has driven the need to understand biol. and medicine at the mol. level. Bioconjugated silica nanoparticles have the potential to address this emerging challenge. Particularly intriguing diagnostic and therapeutic applications in cancer and infectious disease as well as uses in gene and drug delivery, have also been found for silica nanoparticles. In this review, we describe the synthesis, bioconjugation, and applications of silica nanoparticles in different bioanal. formats, such as selective tagging, barcoding, and sepn. of a wide range of biomedically important targets. Overall, we envisage that further development of these nanoparticles will provide a variety of advanced tools for mol. biol., genomics, proteomics and medicine.
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189Petty, A. J.; Keate, R. L.; Jiang, B.; Ameer, G. A.; Rivnay, J. Conducting Polymers for Tissue Regeneration in Vivo †. Chem. Mater. 2020, 32 (10), 4095– 4115, DOI: 10.1021/acs.chemmater.0c00767Google Scholar189https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXnslaqsb0%253D&md5=adc651b2e64de8794e36a1455bab294fConducting Polymers for Tissue Regeneration in VivoPetty, Anthony J.; Keate, Rebecca L.; Jiang, Bin; Ameer, Guillermo A.; Rivnay, JonathanChemistry of Materials (2020), 32 (10), 4095-4115CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)A review. Conducting polymers (CPs) have unique electroactive properties that have inspired significant investigation into their use as biomaterials (CP-BMs) for regenerative engineering. Their phys. and optoelectronic properties, including bulk mixed electronic/ionic conduction, enable the fabrication of a multifunctional biomaterial that passively affects cellular response and modulates elec. field, charge injection, or drug delivery, allowing these materials to actively affect tissue regeneration processes. While material and device dependent cellular responses have been obsd. in vitro, fewer studies have attempted to translate these types of materials and methods to in vivo models. In this Perspective, we assess the CP-BM literature for nerve, spinal cord, bone, and skin regeneration applications with a comprehensive look at in vivo studies, which present an informative illustration of current progress and the state of the field.
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190Rivnay, J.; Wang, H.; Fenno, L.; Deisseroth, K.; Malliaras, G. G. Next-Generation Probes, Particles, and Proteins for Neural Interfacing. Sci. Adv. 2017, 3 (6), e1601649 DOI: 10.1126/sciadv.1601649Google Scholar190https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXmvFOmur4%253D&md5=212e6cb56c64fcba6110beb95f50680eNext-generation probes, particles, and proteins for neural interfacingRivnay, Jonathan; Wang, Huiliang; Fenno, Lief; Deisseroth, Karl; Malliaras, George G.Science Advances (2017), 3 (6), e1601649/1-e1601649/21CODEN: SACDAF; ISSN:2375-2548. (American Association for the Advancement of Science)Bidirectional interfacing with the nervous system enables neuroscience research, diagnosis, and therapy. This two-way communication allows us to monitor the state of the brain and its composite networks and cells as well as to influence them to treat disease or repair/restore sensory or motor function. To provide the most stable and effective interface, the tools of the trade must bridge the soft, ion-rich, and evolving nature of neural tissue with the largely rigid, static realm of microelectronics and medical instruments that allow for readout, anal., and/or control. In this Review, we describe how the understanding of neural signaling and material-tissue interactions has fueled the expansion of the available tool set. New probe architectures and materials, nanoparticles, dyes, and designer genetically encoded proteins push the limits of recording and stimulation lifetime, localization, and specificity, blurring the boundary between living tissue and engineered tools. Understanding these approaches, their modality, and the role of cross-disciplinary development will support new neurotherapies and prostheses and provide neuroscientists and neurologists with unprecedented access to the brain.
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191Kotov, N. A.; Winter, J. O.; Clements, I. P.; Jan, E.; Timko, B. P.; Campidelli, S.; Pathak, S.; Mazzatenta, A.; Lieber, C. M.; Prato, M.; Bellamkonda, R. V.; Silva, G. A.; Kam, N. W. S.; Patolsky, F.; Ballerini, L. Nanomaterials for Neural Interfaces. Adv. Mater. 2009, 21 (40), 3970– 4004, DOI: 10.1002/adma.200801984Google Scholar191https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht12hurrJ&md5=4faa19e4dcf876f7b46b6d5021bbac33Nanomaterials for Neural InterfacesKotov, Nicholas A.; Winter, Jessica O.; Clements, Isaac P.; Jan, Edward; Timko, Brian P.; Campidelli, Stephane; Pathak, Smita; Mazzatenta, Andrea; Lieber, Charles M.; Prato, Maurizio; Bellamkonda, Ravi V.; Silva, Gabriel A.; Kam, Nadine Wong Shi; Patolsky, Fernando; Ballerini, LauraAdvanced Materials (Weinheim, Germany) (2009), 21 (40), 3970-4004CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)This review focuses on the application of nanomaterials for neural interfacing. The junction between nanotechnol. and neural tissues can be particularly worthy of scientific attention for several reasons: (i) Neural cells are electroactive, and the electronic properties of nanostructures can be tailored to match the charge transport requirements of elec. cellular interfacing. (ii) The unique mech. and chem. properties of nanomaterials are crit. for integration with neural tissue as long-term implants. (iii) Solns. to many crit. problems in neural biol./medicine are limited by the availability of specialized materials. (iv) Neuronal stimulation is needed for a variety of common and severe health problems. This confluence of need, accumulated expertise, and potential impact on the well-being of people suggests the potential of nanomaterials to revolutionize the field of neural interfacing. In this review, we begin with foundational topics, such as the current status of neural electrode (NE) technol., the key challenges facing the practical utilization of NEs, and the potential advantages of nanostructures as components of chronic implants. After that the detailed account of toxicol. and biocompatibility of nanomaterials in respect to neural tissues is given. Next, we cover a variety of specific applications of nanoengineered devices, including drug delivery, imaging, topog. patterning, electrode design, nanoscale transistors for high-resoln. neural interfacing, and photoactivated interfaces. We also critically evaluate the specific properties of particular nanomaterials-including nanoparticles, nanowires, and carbon nanotubes-that can be taken advantage of in neuroprosthetic devices. The most promising future areas of research and practical device engineering are discussed as a conclusion to the review.
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192Fattahi, P.; Yang, G.; Kim, G.; Abidian, M. R. A Review of Organic and Inorganic Biomaterials for Neural Interfaces. Adv. Mater. 2014, 26 (12), 1846– 1885, DOI: 10.1002/adma.201304496Google Scholar192https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjtVKhsrg%253D&md5=acdcb2ebe1cb6f81a46c146a15ac693dA Review of Organic and Inorganic Biomaterials for Neural InterfacesFattahi, Pouria; Yang, Guang; Kim, Gloria; Abidian, Mohammad RezaAdvanced Materials (Weinheim, Germany) (2014), 26 (12), 1846-1885CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Recent advances in nanotechnol. have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons. In this comprehensive review, an overview of state-of-the-art microelectrode technologies provided first, with focus on the material properties of these microdevices. The advancements in electro-active nanomaterials are then reviewed, including conducting polymers, carbon nanotubes, graphene, silicon nanowires, and hybrid org.-inorg. nanomaterials, for neural recording, stimulation, and growth. Finally, tech. and scientific challenges are discussed regarding biocompatibility, mech. mismatch, and elec. properties faced by these nanomaterials for the development of long-lasting functional neural interfaces.
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193Wang, M.; Mi, G.; Shi, D.; Bassous, N.; Hickey, D.; Webster, T. J. Nanotechnology and Nanomaterials for Improving Neural Interfaces. Adv. Funct. Mater. 2018, 28 (12), 1700905, DOI: 10.1002/adfm.201700905Google ScholarThere is no corresponding record for this reference.
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194Qu, A.; Sun, M.; Kim, J. Y.; Xu, L.; Hao, C.; Ma, W.; Wu, X.; Liu, X.; Kuang, H.; Kotov, N. A.; Xu, C. Stimulation of Neural Stem Cell Differentiation by Circularly Polarized Light Transduced by Chiral Nanoassemblies. Nat. Biomed. Eng. 2021, 5 (1), 103– 113, DOI: 10.1038/s41551-020-00634-4Google Scholar194https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXitFKlu73J&md5=effe16bd472e2b236252239ba72d2a97Stimulation of neural stem cell differentiation by circularly polarized light transduced by chiral nanoassembliesQu, Aihua; Sun, Maozhong; Kim, Ji-Young; Xu, Liguang; Hao, Changlong; Ma, Wei; Wu, Xiaoling; Liu, Xiaogang; Kuang, Hua; Kotov, Nicholas A.; Xu, ChuanlaiNature Biomedical Engineering (2021), 5 (1), 103-113CODEN: NBEAB3; ISSN:2157-846X. (Nature Research)Abstr.: The biol. effects of circularly polarized light on living cells are considered to be negligibly weak. Here, we show that the differentiation of neural stem cells into neurons can be accelerated by circularly polarized photons when DNA-bridged chiral assemblies of gold nanoparticles are entangled with the cells cytoskeletal fibers. By using cell-culture expts. and plasmonic-force calcns., we demonstrate that the nanoparticle assemblies exert a circularly-polarized-light-dependent force on the cytoskeleton, and that the light-induced periodic mech. deformation of actin nanofibres with a frequency of 50 Hz stimulates the differentiation of neural stem cells into the neuronal phenotype. When implanted in the hippocampus of a mouse model of Alzheimers disease, neural stem cells illuminated following a polarity-optimized protocol reduced the formation of amyloid plaques by more than 70%. Our findings suggest that circularly polarized light can guide cellular development for biomedical use.
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195Kim, T.; McCall, J. G.; Jung, Y. H.; Huang, X.; Siuda, E. R.; Li, Y.; Song, J.; Song, Y. M.; Pao, H. A.; Kim, R.-H. Injectable, Cellular-Scale Optoelectronics with Applications for Wireless Optogenetics. Science (80-.). 2013, 340 (6129), 211– 216, DOI: 10.1126/science.1232437Google ScholarThere is no corresponding record for this reference.
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196Park, K.; Deutsch, Z.; Li, J. J.; Oron, D.; Weiss, S. Single Molecule Quantum-Confined Stark Effect Measurements of Semiconductor Nanoparticles at Room Temperature. ACS Nano 2012, 6 (11), 10013– 10023, DOI: 10.1021/nn303719mGoogle Scholar196https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsFektb3I&md5=5d4a44c41119439686410b5d8ceab834Single Molecule Quantum-Confined Stark Effect Measurements of Semiconductor Nanoparticles at Room TemperaturePark, KyoungWon; Deutsch, Zvicka; Li, J. Jack; Oron, Dan; Weiss, ShimonACS Nano (2012), 6 (11), 10013-10023CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)The authors measured the quantum-confined Stark effect (QCSE) of several types of fluorescent colloidal semiconductor quantum dots and nanorods at the single mol. level at room temp. These measurements demonstrate the possible utility of these nanoparticles for local elec. field (voltage) sensing on the nanoscale. Charge sepn. across one (or more) heterostructure interface(s) with type-II band alignment (and the assocd. induced dipole) is crucial for an enhanced QCSE. To further gain insight into the exptl. results, the authors numerically solved the Schroedinger and Poisson equations under SCF approxn., including dielec. inhomogeneities. Both calcns. and probably the degree of initial charge sepn. (and the assocd. exciton binding energy) dets. the magnitude of the QCSE in these structures.
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197Marshall, J. D.; Schnitzer, M. J. Optical Strategies for Sensing Neuronal Voltage Using Quantum Dots and Other Semiconductor Nanocrystals. ACS Nano 2013, 7 (5), 4601– 4609, DOI: 10.1021/nn401410kGoogle Scholar197https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmtleluro%253D&md5=ef3473b82f43a25f9e500937d82a89f9Optical Strategies for Sensing Neuronal Voltage Using Quantum Dots and Other Semiconductor NanocrystalsMarshall, Jesse D.; Schnitzer, Mark J.ACS Nano (2013), 7 (5), 4601-4609CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Biophysicists have long sought optical methods capable of reporting the electrophysiol. dynamics of large-scale neural networks with millisecond-scale temporal resoln. Existing fluorescent sensors of cell membrane voltage can report action potentials in individual cultured neurons, but limitations in brightness and dynamic range of both synthetic org. and genetically encoded voltage sensors have prevented concurrent monitoring of spiking activity across large populations of individual neurons. Here we propose a novel, inorg. class of fluorescent voltage sensors: semiconductor nanoparticles, such as ultrabright quantum dots (qdots). Our calcns. revealed that transmembrane elec. fields characteristic of neuronal spiking (∼10 mV/nm) modulate a qdot's electronic structure and can induce ∼5% changes in its fluorescence intensity and ∼1 nm shifts in its emission wavelength, depending on the qdot's size, compn., and dielec. environment. Moreover, tailored qdot sensors composed of two different materials can exhibit substantial (∼30%) changes in fluorescence intensity during neuronal spiking. Using signal detection theory, we show that conventional qdots should be capable of reporting voltage dynamics with millisecond precision across several tens or more individual neurons over a range of optical and neurophysiol. conditions. These results unveil promising avenues for imaging spiking dynamics in neural networks and merit in-depth exptl. investigation.
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198Park, K.; Weiss, S. Design Rules for Membrane-Embedded Voltage-Sensing Nanoparticles. Biophys. J. 2017, 112 (4), 703– 713, DOI: 10.1016/j.bpj.2016.12.047Google Scholar198https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1Wnu74%253D&md5=92b969abd0b67af96a78a338ec25af05Design Rules for Membrane-Embedded Voltage-Sensing NanoparticlesPark, Kyoungwon; Weiss, ShimonBiophysical Journal (2017), 112 (4), 703-713CODEN: BIOJAU; ISSN:0006-3495. (Cell Press)Voltage-sensing dyes and voltage-sensing fluorescence proteins have been continually improved and as a result provided a wealth of insights into neuronal circuits. Further improvements in voltage-sensing dyes and voltage-sensing fluorescence proteins are needed, however, for routine detection of single action potentials across a large no. of individual neurons in a large field-of-view of a live mammalian brain. However, recent expts. and calcns. suggest that semiconducting nanoparticles could act as efficient voltage sensors, suitable for the above-mentioned task. This study presents quantum mech. calcns., including Auger recombination rates, of the quantum-confined Stark effect in membrane-embedded semiconducting nanoparticles, examines their possible utility as membrane voltage sensors, and provide design rules for their structure and compn.
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199Caglar, M.; Pandya, R.; Xiao, J.; Foster, S. K.; Divitini, G.; Chen, R. Y. S.; Greenham, N. C.; Franze, K.; Rao, A.; Keyser, U. F. All-Optical Detection of Neuronal Membrane Depolarization in Live Cells Using Colloidal Quantum Dots. Nano Lett. 2019, 19, 8539– 8549, DOI: 10.1021/acs.nanolett.9b03026Google Scholar199https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitVymsrbK&md5=29d0c77990084234e30ebf109e665260All-Optical Detection of Neuronal Membrane Depolarization in Live Cells Using Colloidal Quantum DotsCaglar, Mustafa; Pandya, Raj; Xiao, James; Foster, Sarah K.; Divitini, Giorgio; Chen, Richard Y. S.; Greenham, Neil C.; Franze, Kristian; Rao, Akshay; Keyser, Ulrich F.Nano Letters (2019), 19 (12), 8539-8549CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Luminescent semiconductor quantum dots (QDs) have recently been suggested as novel probes for imaging and sensing cell membrane voltages. However, a key bottleneck for their development is a lack of techniques to assess QD responses to voltages generated in the aq. electrolytic environments typical of biol. systems. Even more generally, there have been relatively few efforts to assess the response of QDs to voltage changes in live cells. Here, the authors develop a platform for monitoring the photoluminescence (PL) response of QDs under AC and DC voltage changes within aq. ionic environments. The authors evaluate both traditional CdSe/CdS and more biol. compatible InP/ZnS QDs at a range of ion concns. to establish their PL/voltage characteristics on chip. Wide-field, few-particle PL measurements with neuronal cells show the QDs can be used to track local voltage changes with greater sensitivity (ΔPL up to twice as large) than state-of-the-art calcium imaging dyes, making them particularly appealing for tracking sub-threshold events. Addnl. physiol. observation studies showed that while CdSe/CdS dots have greater PL responses on membrane depolarization, their lower cytotoxicity makes InP/ZnS far more suitable for voltage sensing in living systems. The results provide a methodol. for the rational development of QD voltage sensors and highlight their potential for imaging changes in cell membrane voltage.
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200Ghosh, S.; Chen, Y.; George, A.; Dutta, M.; Stroscio, M. A. Fluorescence Resonant Energy Transfer-Based Quantum Dot Sensor for the Detection of Calcium Ions. Front. Chem. 2020, 8, 1– 9, DOI: 10.3389/fchem.2020.00594Google ScholarThere is no corresponding record for this reference.
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201Savchenko, A.; Cherkas, V.; Liu, C.; Braun, G. B.; Kleschevnikov, A.; Miller, Y. I.; Molokanova, E. Graphene Biointerfaces for Optical Stimulation of Cells. Sci. Adv. 2018, 4 (5), eaat0351 DOI: 10.1126/sciadv.aat0351Google ScholarThere is no corresponding record for this reference.
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202Barbaglia, A.; Dipalo, M.; Melle, G.; Iachetta, G.; Deleye, L.; Hubarevich, A.; Toma, A.; Tantussi, F.; De Angelis, F. Mirroring Action Potentials: Label-Free, Accurate, and Noninvasive Electrophysiological Recordings of Human-Derived Cardiomyocytes. Adv. Mater. 2021, 33 (7), 2004234, DOI: 10.1002/adma.202004234Google Scholar202https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXosVSjsw%253D%253D&md5=eecb8e2c8fbc74e2b1b17aca8d4869e2Mirroring Action Potentials: Label-Free, Accurate, and Noninvasive Electrophysiological Recordings of Human-Derived CardiomyocytesBarbaglia, Andrea; Dipalo, Michele; Melle, Giovanni; Iachetta, Giuseppina; Deleye, Lieselot; Hubarevich, Aliaksandr; Toma, Andrea; Tantussi, Francesco; De Angelis, FrancescoAdvanced Materials (Weinheim, Germany) (2021), 33 (7), 2004234CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)The electrophysiol. recording of action potentials in human cells is a long-sought objective due to its pivotal importance in many disciplines. Among the developed techniques, invasiveness remains a common issue, causing cytotoxicity or altering unpredictably cell physiol. response. In this work, a new approach for recording intracellular signals of outstanding quality and with noninvasiveness is introduced. By taking profit of the concept of mirror charge in classical electrodynamics, the new proposed device transduces cell ionic currents into mirror charges in a microfluidic chamber, thus realizing a virtual mirror cell. By monitoring mirror charge dynamics, it is possible to effectively record the action potentials fired by the cells. Since there is no need for accessing or interacting with the cells, the method is intrinsically noninvasive. In addn., being based on optical recording, it shows high spatial resoln. and high parallelization. As shown through a set of expts., the presented methodol. is an ideal candidate for the next generation devices for the reliable assessment of cardiotoxicity on human-derived cardiomyocytes. More generally, it paves the way toward a new family of in vitro biodevices that will lay a new milestone in the field of electrophysiol.
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203Iachetta, G.; Colistra, N.; Melle, G.; Deleye, L.; Tantussi, F.; De Angelis, F.; Dipalo, M. Improving Reliability and Reducing Costs of Cardiotoxicity Assessments Using Laser-Induced Cell Poration on Microelectrode Arrays. Toxicol. Appl. Pharmacol. 2021, 418, 115480, DOI: 10.1016/j.taap.2021.115480Google Scholar203https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXnvFeqsrY%253D&md5=3323aacdcb3fdee9a570d1677f8322eeImproving reliability and reducing costs of cardiotoxicity assessments using laser-induced cell poration on microelectrode arraysIachetta, Giuseppina; Colistra, Nicolo; Melle, Giovanni; Deleye, Lieselot; Tantussi, Francesco; De Angelis, Francesco; Dipalo, MicheleToxicology and Applied Pharmacology (2021), 418 (), 115480CODEN: TXAPA9; ISSN:0041-008X. (Elsevier Inc.)Drug-induced cardiotoxicity is a major barrier to drug development and a main cause of withdrawal of marketed drugs. Drugs can strongly alter the spontaneous functioning of the heart by interacting with the cardiac membrane ion channels. If these effects only surface during in vivo preclin. tests, clin. trials or worse after commercialization, the societal and economic burden will be significant and seriously hinder the efficient drug development process. Hence, cardiac safety pharmacol. requires in vitro electrophysiol. screening assays of all drug candidates to predict cardiotoxic effects before clin. trials. In the past 10 years, microelectrode array (MEA) technol. began to be considered a valuable approach in pharmaceutical applications. However, an effective tool for high-throughput intracellular measurements, compatible with pharmaceutical stds., is not yet available. Here, we propose laser-induced optoacoustic poration combined with CMOS-MEA technol. as a reliable and effective platform to detect cardiotoxicity. This approach enables the acquisition of high-quality action potential recordings from large nos. of cardiomyocytes within the same culture well, providing reliable data using single-well MEA devices and single cardiac syncytia per each drug. Thus, this technol. could be applied in drug safety screening platforms reducing times and costs of cardiotoxicity assessments, while simultaneously improving the data reliability.
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Abstract
Figure 1
Figure 1. Applications of semiconductor quantum dots for neurotechnology (top). Schematics for the three main configurations that can lead to neural stimulation using quantum dots (bottom). The free-standing configuration represents the interaction between the targeted cells and the QDs in the extracellular medium without any physical, chemical, or biological attachment to the cell membrane. The second configuration (bottom middle) exhibits the interaction between the targeted cells and the QDs, which may bind to the cell membrane through QD–antibody conjugates or via conjugation with target specific ligands, such as peptides and proteins. The third configuration (bottom right) utilizes QDs in thin-film or blend form. Neuron–QD interaction depends on the chemical, physical, or ionic stimuli generated by QDs.
Figure 2
Figure 2. (a) Quantum dots with stepping emission from blue to red (top). Representative photoluminescence spectrum for different size quantum dots (middle). Representative conduction and valence band diagram for different sizes of semiconductor quantum dots (bottom). (b) Representative TEM images for core/shell quantum dots (scale bars: 20 and 5 nm, respectively). (c) Core/shell semiconductor nanoparticle systems with type I, quasi-type II, and type II band alignment.
Figure 3
Figure 3. (a) Schematic diagram of a generic photovoltaic biointerface architecture. (b) Energy band diagram of a regular (top) and inverted optoelectronic system (bottom). The layers represent the corresponding layers in panel a. The exciton generation occurs in the active layer upon illumination. Dissociated electron and the hole move toward the charge transport layers according to the energy levels between the layers.
Figure 4
Figure 4. Quantum mechanical simulations of type I and type II nanocrystals, showing the effect of wave function engineering on charge carrier localization. (a) Top: Blue lines show energy band alignment and black lines show minimum electron and hole discrete energy levels. R and R+H correspond to the radius of the InP core and the InP/ZnO core/shell QDs, respectively. Bottom: Simulated electron and hole wave functions for the InP core (top) and the InP/ZnO core/shell (bottom) QDs. Black and red lines show electron and hole radial probability functions, respectively. Blue line represents the electron confinement potential. Dashed black and red lines represent single electron and hole energies, respectively. Reprinted with permission from ref (69). Copyright 2018 American Chemical Society. (b) Top: Energy band alignment schematics of type I InP/ZnS and type II InP/ZnO/ZnS QDs. Bottom: Simulated electron (red lines) and hole (black lines) wave functions for InP core, InP/ZnS core/shell, and InP/ZnO/ZnS core/shell/shell nanocrystals. Blue lines represent the electron confinement potential. Reprinted with permission from ref (83). Copyright 2021 Springer Nature. In both studies, type II nanostructures exhibit electron delocalization to shells, which leads to decreased electron–hole wave function overlap, i.e., reduced exciton binding energy.
Figure 5
Figure 5. Primary charge injection mechanisms in QD-based biointerfaces. (a) Illustration of faradaic and capacitive charge injection mechanisms. Electrons or holes accumulate on the biointerface surface, inducing faradaic or capacitive charge injection in the electrolyte (hole accumulation was shown as a representative case). IHP, inner Helmholtz layer, OHP, outer Helmholtz layer, GCL, Gouy–Chapman diffuse-charge layer. (b) Electrical circuit model of the electrode–electrolyte interface. Cdl represents double-layer capacitance and is equivalent to the series sum of IHP, OHP, and GCL capacitances. RCT and Rs denotes charge transfer resistance and solution resistance, respectively. W represents Warburg impedance. (c) Typical current–voltage profiles of resistive and capacitive elements.
Figure 6
Figure 6. Obtaining capacitive-dominant QD-based biointerfaces via donor–acceptor nanoheterojunction (a–c) and band alignment engineering (d, e). (a) Device structure of QD-fullerene donor–acceptor nanoheterojunction-based interfaces for obtaining capacitive-dominant photoresponse. (b) Schematic showing the electron transfer from QD to fullerene derivative PCBM upon photoexcitation. (c) Capacitive photocurrent generation mechanism showing each step in a consecutive manner. Eb, exciton binding energy; Ecb, Evb, Ess, conduction band, valence band, and surface state energy levels, respectively. Band bending at the electrolyte interface prevents electron transfer to electrolyte. Electrons will then be transferred to ZnO and ITO because of the high electron mobility of ZnO. Holes are trapped in the QD valence band because of the ZnO valence band level, which induces capacitive photocurrent. Panels a, b, and c reprinted with permission from ref (83). Copyright 2021 Springer Nature. (d) Schematic of device architecture containing photoactive layers of P3HT:PbS:PCBM, with the intermediate layer (ZnO, MoOx, or none) coated on glass/ITO substrates. Although the photoactive layer generates excitons within the device, the energy level of the intermediate layer determines the surface polarity by routing either the electrons or the holes toward the top surface layer. (e) Manipulation of the band alignment via choice of different intermediate layers. Type I and type II devices generate faradaic-dominant photocurrents due to electron transfer from the PCBM LUMO level to electrolyte. Type III architecture accumulates holes on the surface. Holes do not interact with the electrolyte because of the unfavorable energy level of P3HT HOMO and water oxidation levels, which leads to capacitive-dominant photoresponse. Panels d and e reprinted with permission from ref (71). Copyright 2018 American Physical Society.
Figure 7
Figure 7. Pioneering semiconductor nanoparticle-based optoelectronic neural interfaces. (a) HgTe QDs stabilized with thioglycolic acid-coated single-material device. (b) Light absorption characteristics (1, solid line) and photogenerated voltage (2, bars) of HgTe QDs and layer-by-layer films. UV–vis absorption spectrum on HgTe QD dispersion stabilized by thioglycerol used for fabrication of LBL films. (c) Action potential responses of NG108 cells grown on (PDDA/HgTe)12 + (PDDA/Clay)2 under photostimulus with and without tetrodotoxin (TTX). Panels a, b, and c reprinted with permission from ref (67). Copyright 2007 American Chemcial Society. (d) Schematic of the interaction between a QD and cell membrane. (e) UV–visible absorbance and photoluminescence (PL) characterization of CdTe QDs. (f) Current-clamped recording of cortical neurons on CdSe QD film. Fluorescence image of a micropipette coated with CdSe QDs used for single-cell stimulation. Panels d, e, and f reprinted with permission from ref (68). Copyright 2012 The Optical Society. (g) Schematic of the optoelectronic coupling between NR-conjugated CNT coated by ppAA. (h) Schematic drawing of the CdSe–GSH QDs (left), CdSe/CdS–GSH QDs (center), and CdSe/CdS–GSH NRs (right). Average photocurrents for different devices based on CdSe, CdSe/CdS, and CdSe/CdS NRs with CNTs under an excitation pulse of 30 mW cm–2 for 100 ms with a 405 nm illumination source. (i) (Upper left) SEM image of an NR–CNT film (scale bar: 100 nm). (Upper right) CNT electrode array on a PDMS flexible support (scale bar: 1 mm). (Bottom) Extracellular voltage trace recorded from a chick retina following 100 ms light stimulation (405 nm, pulse interval of 30 ms) under different intensities (1.2, 3, 6, and 12 mW cm–2). Panels g, h, and I reprinted with permission from ref (113). Copyright 2014 American Chemical Society
Figure 8
Figure 8. InP QD-based optoelectronic neural interfaces. (a) Schematic illustration of the photoelectrode fabrication steps and energy band diagram of the device architecture. (b) Photocurrent performance of TiO2, InP core and InP/ZnO QD coated biointerfaces. (c) Photostimulation of a PC12 cell on the photoelectrode under 4 μW mm–2 illumination (red bar, time period under illumination; blue bar, no illumination). Panels a, b and c reprinted with permission from ref (69). Copyright 2018 American Chemical Society. (d) Energy band diagram of bidirectional device architectures. (e) TEM image of the InP/ZnS QDs. (f) Transmembrane potential recordings of neurons on type I, type II, and ITO control samples (illumination: blue LED at 445 nm, 10 ms pulse width, 2 mW mm–2 optical power density; blue bar indicates the 10 ms “light on” interval). Panels d, e, and f reprinted with permission from ref (88). Copyright 2021 Frontiers.
Figure 9
Figure 9. (a) Artificial antenna complexes made of rainbow InP quantum dots showing nonradiative energy transfer toward the cell interface. (b) (Upper inset) Photograph of the colloidal green-, yellow-, and red-emitting QDs under UV illumination. (Bottom) Energy band diagram of the quantum funnel biointerface (c) Photostimulation of the SH-SY5Y cell on the quantum funnel biointerface under illumination of 169 mW cm–2 with 50 ms illumination pulses. Panels a, b, and c reprinted with permission from ref (70). Copyright 2019 American Chemical Society. (d) Energy band alignment of the QD integrated biointerface. InP/ZnS core/shell and InP/ZnO/ZnS core/shell/shell QDs were incorporated into the photoelectrode architecture. (e) Photocurrent density traces of the devices with InP/ZnO/ZnS:PCBM volume ratios of 1:1 (black), 1:3 (red), and 1:7 (orange). The inset shows the components of the photocurrent. Capacitive current is the peak photocurrent reached after the light onset, whereas resistive current is the photocurrent remained after 90% of the illumination duration has passed. (f) Ratios of the capacitive to resistive components for devices with different QD:PCBM mixing ratios. Panels d, e, and f reprinted with permission from ref (83). Copyright 2021 Springer Nature.
Figure 10
Figure 10. PbS- and AlSb-based neural interfaces. (a) (Top) Photocapacitive current levels of ITO/ZnO/P3HT:PCBM and ITO/ZnO/P3HT:PbS-QDs:PCBM photoelectrodes. (Bottom) Capacitive and faradaic components of type I, type II, and type III photoelectrodes under illumination of 10 ms light pulses with an intensity of 1 mW cm–2. The architecture for different types of biointerfaces was explained in panels c and d in Figure 6. (b) Membrane potential variation of SH-SY5Y cells grown on the type III biointerface in panel d upon light illumination (10 ms, 1 mW cm–2). Panels a and b reprinted with permission from ref (71). Copyright 2019 American Physical Society. (c) Atomic force microscopy (5 μm × 5 μm) of P3HT:PCBM surfaces with the optimized binary ratio of 2:1 on ITO/ZnO-coated glass substrates (left, 2D views; right, 3D views) with various thin film thicknesses (t) in tapping-mode. Ra shows the average surface roughness. (d) Peak photocurrent for the binary photoelectrodes as a function of various thin film thicknesses. Panels c and d reprinted with permission from ref (101). Copyright 2020 The Optical Society. (e) Structure of the AlSb integrated biointerface (left inset: cross-sectional SEM image) and energy band diagram of the proposed device. (f) Intracellular membrane potential change with respect to a distant Ag/AgCl electrode was measured after the photostimulation of primary hippocampal neurons on the glass:ITO control (red) and the biointerface (black) under illumination of 100 mW cm–2 with 20 ms illumination pulses. Blue semitransparent area shows the 445 nm light illumination period (g) Successful spike ratio of neurons on the glass:ITO/ZnO/P3HT control (gray) and the biointerface (black) under different illumination frequencies of 20 ms, 50 mW cm–2, and 20 pulses (n = 20, mean ± s.d.). Panels e, f and g reprinted with permission from ref (102). Copyright 2021 Springer Nature.
Figure 11
Figure 11. Biocompatibility of quantum dots for biomedical applications. (a) Oxidation mechanism of Cd-based nanoparticles. Reprinted with permission from ref (164). Copyright 2004 American Chemical Society. (b) Polymer encapsulation strategy for colloidal quantum dots. (A) Native nonpolar ligands remain intact and (B) amphiphilic polymer encapsulate the QD for water solubility. (C) Chemically reactive and polar group for bioconjugation. Reprinted with permission from ref (165). Copyright 2011 Elsevier. (c) Cell viability of hepatocytes as assessed by mitochondrial activity of CdSe QD-treated cultures relative to untreated controls under exposure to air and UV treatment. Reprinted with permission from ref (164). Copyright 2004 American Chemical Society. (d) Effect of ZnS coating on CdSe quantum dots on cytotoxicity and oxidation. Reprinted with permission from ref (164). Copyright 2004 American Chemical Society. (e) Cell viability of MCF-7 cells incubated with different concentrations of InP/ZnS QDs and CdSe/ZnS QDs for 24 h. Reprinted with permission from ref (167). Copyright 2017, Royal Society of Chemistry. (f) Cell viability and cytotoxicity assessment of InP/ZnO quantum dots with MTT (upper left), LDH assay (upper right), and visualized cell morphology via DAPI staining and actin immunolabeling (bottom, scale bar: 50 μm). Reprinted with permission from ref (69). Copyright 2018 American Chemical Society. (g) Immunofluorescence imaging of primary hippocampal neurons grown on AlSb NC-coated biointerfaces. PHNs costained with DAPI, Anti-NeuN (red), and anti-F-actin (green) (scale bar: 75 μm). Reprinted with permission from ref (102). Copyright 2021 Springer Nature.
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References
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This article references 203 other publications.
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1Cingolani, E.; Goldhaber, J. I.; Marbán, E. Next-Generation Pacemakers: From Small Devices to Biological Pacemakers. Nat. Rev. Cardiol. 2018, 15 (3), 139– 150, DOI: 10.1038/nrcardio.2017.1651https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1M3hvVaitA%253D%253D&md5=a9393f0913b760956c5a9cedc7273381Next-generation pacemakers: from small devices to biological pacemakersCingolani Eugenio; Goldhaber Joshua I; Marban EduardoNature reviews. Cardiology (2018), 15 (3), 139-150 ISSN:.Electrogenesis in the heart begins in the sinoatrial node and proceeds down the conduction system to originate the heartbeat. Conduction system disorders lead to slow heart rates that are insufficient to support the circulation, necessitating implantation of electronic pacemakers. The typical electronic pacemaker consists of a subcutaneous generator and battery module attached to one or more endocardial leads. New leadless pacemakers can be implanted directly into the right ventricular apex, providing single-chamber pacing without a subcutaneous generator. Modern pacemakers are generally reliable, and their programmability provides options for different pacing modes tailored to specific clinical needs. Advances in device technology will probably include alternative energy sources and dual-chamber leadless pacing in the not-too-distant future. Although effective, current electronic devices have limitations related to lead or generator malfunction, lack of autonomic responsiveness, undesirable interactions with strong magnetic fields, and device-related infections. Biological pacemakers, generated by somatic gene transfer, cell fusion, or cell transplantation, provide an alternative to electronic devices. Somatic reprogramming strategies, which involve transfer of genes encoding transcription factors to transform working myocardium into a surrogate sinoatrial node, are furthest along in the translational pipeline. Even as electronic pacemakers become smaller and less invasive, biological pacemakers might expand the therapeutic armamentarium for conduction system disorders.
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2Chaudhary, U.; Mrachacz-Kersting, N.; Birbaumer, N. Neuropsychological and Neurophysiological Aspects of Brain-Computer-Interface (BCI) Control in Paralysis. J. Physiol. 2021, 599 (9), 2351– 2359, DOI: 10.1113/JP2787752https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXlsl2gt7k%253D&md5=7345cd054417bc47cec98ca33b29e066Neuropsychological and neurophysiological aspects of brain-computer-interface (BCI) control in paralysisChaudhary, Ujwal; Mrachacz-Kersting, Natalie; Birbaumer, NielsJournal of Physiology (Oxford, United Kingdom) (2021), 599 (9), 2351-2359CODEN: JPHYA7; ISSN:1469-7793. (Wiley-Blackwell)Brain-computer interfaces (BCIs) aim to help paralysed patients to interact with their environment by controlling external devices using brain activity, thereby bypassing the dysfunctional motor system. Some neuronal disorders, such as amyotrophic lateral sclerosis (ALS), severely impair the communication capacity of patients. Several invasive and non-invasive brain-computer interfaces (BCIs), most notably using electroencephalog. (EEG), have been developed to provide a means of communication to paralysed patients. However, except for a few reports, all available BCI literature for the paralysed (mostly ALS patients) describes patients with intact eye movement control, i.e. patients in a locked-in state (LIS) but not a completely locked-in state (CLIS). In this article we will discuss: (1) the fundamental neuropsychol. learning factors and neurophysiol. factors detg. BCI performance in clin. applications; (2) the difference between LIS and CLIS; (3) recent development in BCIs for communication with patients in the completely locked-in state; (4) the effect of BCI-based communication on emotional well-being and quality of life; and (5) the outlook and the methodol. needed to provide a means of communication for patients who have none. Thus, we present an overview of available studies and recent results and try to anticipate future developments which may open new doors for BCI communication with the completely paralysed.
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3Wu, Y.-C.; Liao, Y.-S.; Yeh, W.-H.; Liang, S.-F.; Shaw, F.-Z. Directions of Deep Brain Stimulation for Epilepsy and Parkinson’s Disease. Frontiers in Neuroscience. 2021, 15, 671, DOI: 10.3389/fnins.2021.680938There is no corresponding record for this reference.
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4Lozano, A. M.; Lipsman, N.; Bergman, H.; Brown, P.; Chabardes, S.; Chang, J. W.; Matthews, K.; McIntyre, C. C.; Schlaepfer, T. E.; Schulder, M.; Temel, Y.; Volkmann, J.; Krauss, J. K. Deep Brain Stimulation: Current Challenges and Future Directions. Nat. Rev. Neurol. 2019, 15 (3), 148– 160, DOI: 10.1038/s41582-018-0128-24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3cjlsVOquw%253D%253D&md5=f8f92cb8f144f4c86ed741decc1ff737Deep brain stimulation: current challenges and future directionsLozano Andres M; Lipsman Nir; Bergman Hagai; Brown Peter; Chabardes Stephan; Chang Jin Woo; Matthews Keith; McIntyre Cameron C; Schlaepfer Thomas E; Schulder Michael; Temel Yasin; Volkmann Jens; Krauss Joachim KNature reviews. Neurology (2019), 15 (3), 148-160 ISSN:.The clinical use of deep brain stimulation (DBS) is among the most important advances in the clinical neurosciences in the past two decades. As a surgical tool, DBS can directly measure pathological brain activity and can deliver adjustable stimulation for therapeutic effect in neurological and psychiatric disorders correlated with dysfunctional circuitry. The development of DBS has opened new opportunities to access and interrogate malfunctioning brain circuits and to test the therapeutic potential of regulating the output of these circuits in a broad range of disorders. Despite the success and rapid adoption of DBS, crucial questions remain, including which brain areas should be targeted and in which patients. This Review considers how DBS has facilitated advances in our understanding of how circuit malfunction can lead to brain disorders and outlines the key unmet challenges and future directions in the DBS field. Determining the next steps in DBS science will help to define the future role of this technology in the development of novel therapeutics for the most challenging disorders affecting the human brain.
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5Jeong, Y. C.; Lee, H. E.; Shin, A.; Kim, D. G.; Lee, K. J.; Kim, D. Progress in Brain-Compatible Interfaces with Soft Nanomaterials. Adv. Mater. 2020, 32 (35), 1907522, DOI: 10.1002/adma.2019075225https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXntFGgsLw%253D&md5=b5ab35e1efca3c83ef3bc86a171dec1fProgress in Brain-Compatible Interfaces with Soft NanomaterialsJeong, Yong-Cheol; Lee, Han Eol; Shin, Anna; Kim, Dae-Gun; Lee, Keon Jae; Kim, DaesooAdvanced Materials (Weinheim, Germany) (2020), 32 (35), 1907522CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Neural interfaces facilitating communication between the brain and machines must be compatible with the soft, curvilinear, and elastic tissues of the brain and yet yield enough power to read and write information across a wide range of brain areas through high-throughput recordings or optogenetics. Biocompatible-material engineering has facilitated the development of brain-compatible neural interfaces to support built-in modulation of neural circuits and neurol. disorders. Recent developments in brain-compatible neural interfaces that use soft nanomaterials more suitable for complex neural circuit anal. and modulation are reviewed. Preclin. tests of the compatibility and specificity of these interfaces in animal models are also discussed.
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6Won, S. M.; Cai, L.; Gutruf, P.; Rogers, J. A. Wireless and Battery-Free Technologies for Neuroengineering. Nat. Biomed. Eng. 2021, DOI: 10.1038/s41551-021-00683-3 .There is no corresponding record for this reference.
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7Kuo, C. H.; White-Dzuro, G. A.; Ko, A. L. Approaches to Closed-Loop Deep Brain Stimulation for Movement Disorders. Neurosurg. Focus 2018, 45 (2), E2 DOI: 10.3171/2018.5.FOCUS18173There is no corresponding record for this reference.
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8Gentet, L. J.; Stuart, G. J.; Clements, J. D. Direct Measurement of Specific Membrane Capacitance in Neurons. Biophys. J. 2000, 79 (1), 314– 320, DOI: 10.1016/S0006-3495(00)76293-X8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXks1Kksr0%253D&md5=c691b4ddb0dcdcd50d248f6c150ff1c8Direct measurement of specific membrane capacitance in neuronsGentet, Luc J.; Stuart, Greg J.; Clements, John D.Biophysical Journal (2000), 79 (1), 314-320CODEN: BIOJAU; ISSN:0006-3495. (Biophysical Society)The specific membrane capacitance (Cm) of a neuron influences synaptic efficacy and dets. the speed with which elec. signals propagate along dendrites and unmyelinated axons. The value of this important parameter remains controversial. In this study, Cm was estd. for the somatic membrane of cortical pyramidal neurons, spinal cord neurons, and hippocampal neurons. A nucleated patch was pulled and a voltage-clamp step was applied. The exponential decay of the capacitative charging current was analyzed to give the total membrane capacitance, which was then divided by the obsd. surface area of the patch. Cm was 0.9 μF/cm2 for each class of neuron. To test the possibility that membrane proteins may alter Cm, embryonic kidney cells (HEK-293) were studied before and after transfection with a plasmid coding for glycine receptor/channels. The value of Cm was indistinguishable in untransfected cells and in transfected cells expressing a high level of glycine channels, indicating that differences in transmembrane protein content do not significantly affect Cm. Thus, to a first approxn., Cm may be treated as a "biol. const." across many classes of neuron.
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9Hanifi, D. A.; Bronstein, N. D.; Koscher, B. A.; Nett, Z.; Swabeck, J. K.; Takano, K.; Schwartzberg, A. M.; Maserati, L.; Vandewal, K.; van de Burgt, Y.; Salleo, A.; Alivisatos, A. P. Redefining Near-Unity Luminescence in Quantum Dots with Photothermal Threshold Quantum Yield. Science (80-.). 2019, 363 (6432), 1199– 1202, DOI: 10.1126/science.aat3803There is no corresponding record for this reference.
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10Won, Y. H.; Cho, O.; Kim, T.; Chung, D. Y.; Kim, T.; Chung, H.; Jang, H.; Lee, J.; Kim, D.; Jang, E. Highly Efficient and Stable InP/ZnSe/ZnS Quantum Dot Light-Emitting Diodes. Nature 2019, 575 (7784), 634– 638, DOI: 10.1038/s41586-019-1771-510https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXit1OhsrvP&md5=30a54f042a52e47575f0c9db1f9532b2Highly efficient and stable InP/ZnSe/ZnS quantum dot light-emitting diodesWon, Yu-Ho; Cho, Oul; Kim, Taehyung; Chung, Dae-Young; Kim, Taehee; Chung, Heejae; Jang, Hyosook; Lee, Junho; Kim, Dongho; Jang, EunjooNature (London, United Kingdom) (2019), 575 (7784), 634-638CODEN: NATUAS; ISSN:0028-0836. (Nature Research)Quantum dot (QD) light-emitting diodes (LEDs) are ideal for large-panel displays because of their excellent efficiency, color purity, reliability and cost-effective fabrication. Intensive efforts have produced red-, green- and blue-emitting QD-LEDs with efficiencies of 20.5 per cent4, 21.0 per cent and 19.8 per cent, resp., but it is still desirable to improve the operating stability of the devices and to replace their toxic cadmium compn. with a more environmentally benign alternative. The performance of indium phosphide (InP)-based materials and devices has remained far behind those of their Cd-contg. counterparts. Here we present a synthetic method of prepg. a uniform InP core and a highly sym. core/shell QD with a quantum yield of approx. 100 per cent. In particular, we add hydrofluoric acid to etch out the oxidative InP core surface during the growth of the initial ZnSe shell and then we enable high-temp. ZnSe growth at 340 °C. The engineered shell thickness suppresses energy transfer and Auger recombination in order to maintain high luminescence efficiency, and the initial surface ligand is replaced with a shorter one for better charge injection. The optimized InP/ZnSe/ZnS QD-LEDs showed a theor. max. external quantum efficiency of 21.4 per cent, a max. brightness of 100,000 candelas per square metre and an extremely long lifetime of a million hours at 100 candelas per square metre, representing a performance comparable to that of state-of-the-art Cd-contg. QD-LEDs. These as-prepd. InP-based QD-LEDs could soon be usable in com. displays.
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11Shirasaki, Y.; Supran, G. J.; Bawendi, M. G.; Bulović, V. Emergence of Colloidal Quantum-Dot Light-Emitting Technologies. Nat. Photonics 2013, 7 (1), 13– 23, DOI: 10.1038/nphoton.2012.32811https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhvV2ntLfI&md5=9ce4673b68f86faa7c83212c053193c4Emergence of colloidal quantum-dot light-emitting technologiesShirasaki, Yasuhiro; Supran, Geoffrey J.; Bawendi, Moungi G.; Bulovic, VladimirNature Photonics (2013), 7 (1), 13-23CODEN: NPAHBY; ISSN:1749-4885. (Nature Publishing Group)A review. Since their inception 18 years ago, elec. driven colloidal quantum-dot light-emitting devices (QD-LEDs) have increased in external quantum efficiency from less than 0.01% to around 18%. The high luminescence efficiency and uniquely size-tunable color of soln.-processable semiconducting colloidal QDs highlight the potential of QD-LEDs for use in energy-efficient, high-color-quality thin-film display and solid-state lighting applications. Indeed, last year saw the first demonstrations of elec. driven full-color QD-LED displays, which foreshadow QD technologies that will transcend the optically excited QD-enhanced lighting products already available today. We here discuss the key advantages of using QDs as luminophores in LEDs and outline the operating mechanisms of four types of QD-LED. State-of-the-art visible-wavelength LEDs and the promise of near-IR and heavy-metal-free devices are also highlighted. As QD-LED efficiencies approach those of mol. org. LEDs, we identify the key scientific and technol. challenges facing QD-LED commercialization and offer our outlook for on-going strategies to overcome these challenges.
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12Pal, B. N.; Robel, I.; Mohite, A.; Laocharoensuk, R.; Werder, D. J.; Klimov, V. I. High-Sensitivity p-n Junction Photodiodes Based on Pbs Nanocrystal Quantum Dots. Adv. Funct. Mater. 2012, 22 (8), 1741– 1748, DOI: 10.1002/adfm.20110253212https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xit1eitbw%253D&md5=b7a7b323a452b111c3a9171122539ec0High-Sensitivity p-n Junction Photodiodes Based on PbS Nanocrystal Quantum DotsPal, Bhola N.; Robel, Istvan; Mohite, Aditya; Laocharoensuk, Rawiwan; Werder, Donald J.; Klimov, Victor I.Advanced Functional Materials (2012), 22 (8), 1741-1748CODEN: AFMDC6; ISSN:1616-301X. (Wiley-VCH Verlag GmbH & Co. KGaA)Chem. synthesized nanocrystal quantum dots (NQDs) are promising materials for applications in soln.-processable optoelectronic devices such as light emitting diodes, photodetectors, and solar cells. Here, the authors fabricate and study two types of p-n junction photodiodes in which the photoactive p-layer is made from PbS NQDs while the transparent n-layer is fabricated from wide bandgap oxides (ZnO or TiO2). By using a p-n junction architecture the authors are able to significantly reduce the dark current compared to earlier Schottky junction devices without reducing external quantum efficiency (EQE), which reaches values of up to ∼80%. The use of this device architecture also allows the authors to significantly reduce noise and obtain high detectivity (>1012 cm Hz1/2 W-1) extending to the near IR past 1 μm. The spectral shape of the photoresponse exhibits a significant dependence on applied bias, and specifically, the EQE sharply increases around 500-600 nm at reverse biases >1 V. The authors attribute this behavior to a turn-on of an addnl. contribution to the photocurrent due to electrons excited to the conduction band from the occupied mid-gap states.
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13Konstantatos, G.; Howard, I.; Fischer, A.; Hoogland, S.; Clifford, J.; Klem, E.; Levina, L.; Sargent, E. H. Ultrasensitive Solution-Cast Quantum Dot Photodetectors. Nature 2006, 442 (7099), 180– 183, DOI: 10.1038/nature0485513https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XmvFahtb4%253D&md5=3170d6484c19a8db1e9858804a720953Ultrasensitive solution-cast quantum dot photodetectorsKonstantatos, Gerasimos; Howard, Ian; Fischer, Armin; Hoogland, Sjoerd; Clifford, Jason; Klem, Ethan; Levina, Larissa; Sargent, Edward H.Nature (London, United Kingdom) (2006), 442 (7099), 180-183CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Soln.-processed electronic and optoelectronic devices offer low cost, large device area, phys. flexibility and convenient materials integration compared to conventional epitaxially grown, lattice-matched, cryst. semiconductor devices. Although the electronic or optoelectronic performance of these soln.-processed devices is typically inferior to that of those fabricated by conventional routes, this can be tolerated for some applications in view of the other benefits. Here we report the fabrication of soln.-processed IR photodetectors that are superior in their normalized detectivity (D*, the figure of merit for detector sensitivity) to the best epitaxially grown devices operating at room temp. We produced the devices in a single soln.-processing step, overcoating a prefabricated planar electrode array with an unpatterned layer of PbS colloidal quantum dot nanocrystals. The devices showed large photoconductive gains with responsivities greater than 103 A W-1. The best devices exhibited a normalized detectivity D* of 1.8 × 1013 jones (1 jones = 1 cm Hz1/2 W-1) at 1.3 μm at room temp.: today's highest performance IR photodetectors are photovoltaic devices made from epitaxially grown InGaAs that exhibit peak D* in the 1012 jones range at room temp., whereas the previous record for D* from a photoconductive detector lies at 1011 jones. The tailored selection of absorption onset energy through the quantum size effect, combined with deliberate engineering of the sequence of nanoparticle fusing and surface trap functionalization, underlie the superior performance achieved in this readily fabricated family of devices.
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14Pattantyus-Abraham, A. G.; Kramer, I. J.; Barkhouse, A. R.; Wang, X.; Konstantatos, G.; Debnath, R.; Levina, L.; Raabe, I.; Nazeeruddin, M. K.; Grätzel, M.; Sargent, E. H. Depleted-Heterojunction Colloidal Quantum Dot Solar Cells. ACS Nano 2010, 4 (6), 3374– 3380, DOI: 10.1021/nn100335g14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXmsVGjsL8%253D&md5=b320b0603492a00bd1c6bb6e88c52c30Depleted-Heterojunction Colloidal Quantum Dot Solar CellsPattantyus-Abraham, Andras G.; Kramer, Illan J.; Barkhouse, Aaron R.; Wang, Xihua; Konstantatos, Gerasimos; Debnath, Ratan; Levina, Larissa; Raabe, Ines; Nazeeruddin, Mohammad K.; Gratzel, Michael; Sargent, Edward H.ACS Nano (2010), 4 (6), 3374-3380CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Colloidal quantum dot photovoltaics combine low-cost soln. processability with quantum size-effect tunability to match absorption with the solar spectrum. Rapid recent advances in colloidal quantum dot photovoltaics have led to impressive 3.6% air-mass 1.5 solar power conversion efficiencies. Two distinct device architectures and operating mechanisms have been advanced. The first, the Schottky device, was optimized and explained in terms of a depletion region driving electron-hole pair sepn. on the semiconductor side of a junction between an opaque low-work-function metal and a p-type colloidal quantum dot film. The second, the excitonic device, employed a colloidal quantum dot layer atop a transparent conductive oxide and was explained in terms of diffusive exciton transport via energy transfer followed by exciton sepn. at the type-II heterointerface between the colloidal quantum dot film and the transparent conductive oxide. Here we fabricate colloidal quantum dot photovoltaic devices on transparent conductive oxides and show that our devices rely on the establishment of a depletion region for field-driven charge transport and sepn., and that they also exploit the large bandgap of the transparent conductive oxide to improve rectification and block undesired hole extn. The resultant depleted-heterojunction solar cells provide a 5.1% air-mass 1.5 power conversion efficiency. The devices employ IR-bandgap size-effect-tuned PbS colloidal quantum dots, enabling broadband harvesting of the solar spectrum. We report the highest open-circuit voltages obsd. in solid-state colloidal quantum dot solar cells to date, as well as fill factors approaching 60%, through the combination of efficient hole blocking (heterojunction) and very small minority carrier d. (depletion) in the large-bandgap moiety.
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15Conibeer, G. Third-Generation Photovoltaics. Mater. Today 2007, 10 (11), 42– 50, DOI: 10.1016/S1369-7021(07)70278-X15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXhtlGgs7bK&md5=f2c7fb746d26e7b1027585ed76c26865Third-generation photovoltaicsConibeer, GavinMaterials Today (Oxford, United Kingdom) (2007), 10 (11), 42-50CODEN: MTOUAN; ISSN:1369-7021. (Elsevier Ltd.)Third-generation approaches to photovoltaics (PVs) aim to achieve high-efficiency devices but still use thin-film, 2nd-generation deposition methods. The concept is to do this with only a small increase in areal costs and hence reduce the cost per W peak (this metric is the most widely used in the PV industry). Also, in common with Si-based, 2nd-generation, thin-film technologies, these will use materials that are both nontoxic and not limited in abundance. Thus, these 3rd-generation technologies will be compatible with large-scale implementation of PVs. The approach differs from 1st-generation fabrication of high-quality, low-defect, single-crystal PV devices that have high efficiencies approaching the limiting efficiencies for single-bandgap devices but use energy- and time-intensive techniques.
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16Konstantatos, G.; Badioli, M.; Gaudreau, L.; Osmond, J.; Bernechea, M.; De Arquer, F. P. G.; Gatti, F.; Koppens, F. H. L. Hybrid Graphene Quantum Dot Phototransistors with Ultrahigh Gain. Nat. Nanotechnol. 2012, 7 (6), 363– 368, DOI: 10.1038/nnano.2012.6016https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XmsFOqsrs%253D&md5=d13d35fc059cdd63c5c1189123af8582Hybrid graphene-quantum dot phototransistors with ultrahigh gainKonstantatos, Gerasimos; Badioli, Michela; Gaudreau, Louis; Osmond, Johann; Bernechea, Maria; de Arquer, F. Pelayo Garcia; Gatti, Fabio; Koppens, Frank H. L.Nature Nanotechnology (2012), 7 (6), 363-368CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)Graphene is an attractive material for optoelectronics and photodetection applications because it offers a broad spectral bandwidth and fast response times. Weak light absorption and the absence of a gain mechanism that can generate multiple charge carriers from 1 incident photon have limited the responsivity of graphene-based photodetectors to ∼10-2 A W-1. A gain of ∼108 electrons per photon and a responsivity of ∼107 A W-1 in a hybrid photodetector that consists of monolayer or bilayer graphene covered with a thin film of PbS colloidal quantum dots is demonstrated. Strong and tunable light absorption in the quantum-dot layer creates elec. charges that are transferred to the graphene, where they recirculate many times due to the high charge mobility of graphene and long trapped-charge lifetimes in the quantum-dot layer. The device, with a specific detectivity of 7 × 1013 Jones, benefits from gate-tunable sensitivity and speed, spectral selectivity from the short-wavelength IR to the visible, and compatibility with current circuit technols.
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17Bruchez, M.; Moronne, M.; Gin, P.; Weiss, S.; Alivisatos, A. P. Semiconductor Nanocrystals as Fluorescent Biological Labels. Science (80-.). 1998, 281 (5385), 2013– 2016, DOI: 10.1126/science.281.5385.201317https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtlKgurw%253D&md5=db36fdbbfbc2facf264c3f98c1c8efcbSemiconductor nanocrystals as fluorescent biological labelsBruchez, Marcel, Jr.; Moronne, Mario; Gin, Peter; Weiss, Shimon; Alivisatos, A. PaulScience (Washington, D. C.) (1998), 281 (5385), 2013-2016CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Semiconductor nanocrystals were prepd. for use as fluorescent probes in biol. staining and diagnostics. Compared with conventional fluorophores, the nanocrystals have a narrow, tunable, sym. emission spectrum and are photochem. stable. The advantages of the broad, continuous excitation spectrum were demonstrated in a dual-emission, single-excitation labeling expt. on mouse fibroblasts. These nanocrystal probes are thus complementary and in some cases may be superior to existing fluorophores.
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18Biju, V.; Itoh, T.; Ishikawa, M. Delivering Quantum Dots to Cells: Bioconjugated Quantum Dots for Targeted and Nonspecific Extracellular and Intracellular Imaging. Chem. Soc. Rev. 2010, 39 (8), 3031– 3056, DOI: 10.1039/b926512k18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXptFygs7c%253D&md5=44314b2f8c76d4da56b63ceb1dc3a60aDelivering quantum dots to cells: bioconjugated quantum dots for targeted and nonspecific extracellular and intracellular imagingBiju, Vasudevanpillai; Itoh, Tamitake; Ishikawa, MitsuruChemical Society Reviews (2010), 39 (8), 3031-3056CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)A review. Bioconjugated nanomaterials offer endless opportunities to advance both nanobiotechnol. and biomedical technol. In this regard, semiconductor nanoparticles, also called quantum dots, are of particular interest for multimodal, multifunctional and multiplexed imaging of biomols., cells, tissues and animals. The unique optical properties, such as size-dependent tunable absorption and emission in the visible and NIR regions, narrow emission and broad absorption bands, high photoluminescence quantum yields, large one- and multi-photon absorption cross-sections, and exceptional photostability are the advantages of quantum dots. Multimodal imaging probes are developed by interfacing the unique optical properties of quantum dots with magnetic or radioactive materials. Besides, cryst. structure of quantum dots adds scope for high-contrast x-ray and TEM imaging. Yet another unique feature of a quantum dot is its spacious and flexible surface which is promising to integrate multiple ligands and antibodies and construct multi-functional probes for bioimaging. In this crit. review, the authors will summarize recent advancements in the prepn. of biocompatible quantum dots, bioconjugation of quantum dots, and applications of quantum dots and their bioconjugates for targeted and nonspecific imaging of extracellular and intracellular proteins, organelles and functions (181 refs.).
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19Tada, H.; Higuchi, H.; Wanatabe, T. M.; Ohuchi, N. In Vivo Real-Time Tracking of Single Quantum Dots Conjugated with Monoclonal Anti-HER2 Antibody in Tumors of Mice. Cancer Res. 2007, 67 (3), 1138– 1144, DOI: 10.1158/0008-5472.CAN-06-118519https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXht1ynsLg%253D&md5=e472812ca77edd3c0192d6e1f3cb7b15In vivo Real-time Tracking of Single Quantum Dots Conjugated with Monoclonal Anti-HER2 Antibody in Tumors of MiceTada, Hiroshi; Higuchi, Hideo; Wanatabe, Tomonobu M.; Ohuchi, NoriakiCancer Research (2007), 67 (3), 1138-1144CODEN: CNREA8; ISSN:0008-5472. (American Association for Cancer Research)Studies with tracking of single nanoparticles are providing new insights into the interactions and processes involved in the transport of drug carriers in living mice. Here, the authors report the tracking of a single particle quantum dot (Qdot) conjugated with tumor-targeting antibody in tumors of living mice using a dorsal skinfold chamber and a high-speed confocal microscope with a high-sensitivity camera. Qdot labeled with the monoclonal anti-HER2 antibody was injected into mice with HER2-overexpressing breast cancer to analyze the mol. processes of its mechanistic delivery to the tumor. Movement of single complexes of the Qdot-antibody could be clearly obsd. at 30 frames/s inside the tumor through a dorsal skinfold chamber. The authors successfully identified six processes of delivery: initially in the circulation within a blood vessel, during extravasation, in the extracellular region, binding to HER2 on the cell membrane, moving from the cell membrane to the perinuclear region, and in the perinuclear region. The six processes were quant. analyzed to understand the rate-limiting constraints on Qdot-antibody delivery. The movement of the complexes at each stage was "stop-and-go.". The image anal. of the delivery processes of single particles in vivo provides valuable information on antibody-conjugated therapeutic nanoparticles, which will be useful in increasing therapeutic efficacy.
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20Michalet, X.; Pinaud, F. F.; Bentolila, L. A.; Tsay, J. M.; Doose, S.; Li, J. J.; Sundaresan, G.; Wu, A. M.; Gambhir, S. S.; Weiss, S. Quantum Dots for Live Cells, in Vivo Imaging, and Diagnostics. Science (80-.). 2005, 307 (5709), 538– 544, DOI: 10.1126/science.110427420https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmslOhtw%253D%253D&md5=03a28864cfd8c3c4269cc9919d1eafb9Quantum Dots for Live Cells, in Vivo Imaging, and DiagnosticsMichalet, X.; Pinaud, F. F.; Bentolila, L. A.; Tsay, J. M.; Doose, S.; Li, J. J.; Sundaresan, G.; Wu, A. M.; Gambhir, S. S.; Weiss, S.Science (Washington, DC, United States) (2005), 307 (5709), 538-544CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)A review. Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biol. applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biol. Recent examples of their exptl. use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-IR emission during surgery. The new generations of qdots have far-reaching potential for the study of intracellular processes at the single-mol. level, high-resoln. cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
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21Gao, X.; Cui, Y.; Levenson, R. M.; Chung, L. W. K.; Nie, S. In Vivo Cancer Targeting and Imaging with Semiconductor Quantum Dots. Nat. Biotechnol. 2004, 22 (8), 969– 976, DOI: 10.1038/nbt99421https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXmtFWru74%253D&md5=0762e06fe115b89ff1fc23a8959c9cc1In vivo cancer targeting and imaging with semiconductor quantum dotsGao, Xiaohu; Cui, Yuanyuan; Levenson, Richard M.; Chung, Leland W. K.; Nie, ShumingNature Biotechnology (2004), 22 (8), 969-976CODEN: NABIF9; ISSN:1087-0156. (Nature Publishing Group)We describe the development of multifunctional nanoparticle probes based on semiconductor quantum dots (QDs) for cancer targeting and imaging in living animals. The structural design involves encapsulating luminescent QDs with an ABC triblock copolymer and linking this amphiphilic polymer to tumor-targeting ligands and drug-delivery functionalities. In vivo targeting studies of human prostate cancer growing in nude mice indicate that the QD probes accumulate at tumors both by the enhanced permeability and retention of tumor sites and by antibody binding to cancer-specific cell surface biomarkers. Using both s.c. injection of QD-tagged cancer cells and systemic injection of multifunctional QD probes, we have achieved sensitive and multicolor fluorescence imaging of cancer cells under in vivo conditions. We have also integrated a whole-body macro-illumination system with wavelength-resolved spectral imaging for efficient background removal and precise delineation of weak spectral signatures. These results raise new possibilities for ultrasensitive and multiplexed imaging of mol. targets in vivo.
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22Efros, A. L.; Delehanty, J. B.; Huston, A. L.; Medintz, I. L.; Barbic, M.; Harris, T. D. Evaluating the Potential of Using Quantum Dots for Monitoring Electrical Signals in Neurons. Nat. Nanotechnol. 2018, 13 (4), 278– 288, DOI: 10.1038/s41565-018-0107-122https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXnsVeitLk%253D&md5=49901bf15ccf92fa34e835c1ef1b2e9bEvaluating the potential of using quantum dots for monitoring electrical signals in neuronsEfros, Alexander L.; Delehanty, James B.; Huston, Alan L.; Medintz, Igor L.; Barbic, Mladen; Harris, Timothy D.Nature Nanotechnology (2018), 13 (4), 278-288CODEN: NNAABX; ISSN:1748-3387. (Nature Research)A review. Success in the projects aimed at providing an advanced understanding of the brain is directly predicated on making crit. advances in nanotechnol. This Perspective addresses the unique interface of neuroscience and nanomaterials by considering the foundational problem of sensing neuron membrane voltage and offers a potential soln. that may be facilitated by a prototypical nanomaterial. Despite substantial improvements, the visualization of instantaneous voltage changes within individual neurons, whether in cell culture or in vivo, at both the single-cell and network level at high speed remains complex and problematic. The unique properties of semiconductor quantum dots (QDs) have made them powerful fluorophores for bioimaging. What is not widely appreciated, however, is that QD photoluminescence is exquisitely sensitive to proximal elec. fields. This property should be suitable for sensing voltage changes that occur in the active neuronal membrane. Here, we examine the potential role of QDs in addressing the important challenge of real-time optical voltage imaging.
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23Wang, Y.; Hu, R.; Lin, G.; Roy, I.; Yong, K.-T. Functionalized Quantum Dots for Biosensing and Bioimaging and Concerns on Toxicity. ACS Appl. Mater. Interfaces 2013, 5 (8), 2786– 2799, DOI: 10.1021/am302030a23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXit1eit78%253D&md5=6c35e87b022e0d76a112a83b31caa384Functionalized Quantum Dots for Biosensing and Bioimaging and Concerns on ToxicityWang, Yucheng; Hu, Rui; Lin, Guimiao; Roy, Indrajit; Yong, Ken-TyeACS Applied Materials & Interfaces (2013), 5 (8), 2786-2799CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)A review. Considerable efforts have been devoted to the development of novel functionalized nanomaterials for bio-oriented applications. With unique optical properties and molar scale prodn., colloidal photoluminescent quantum dots (QDs) have been properly functionalized with controlled interfaces as new class of optical probes with extensive use in biomedical research. In this review, we present a brief summary on the current research interests of using fine engineered QDs as a nanoplatform for biomedical sensing and imaging applications. In addn., recent concerns on the potential toxic effects of QDs are described as a general guidance for the development on QD formulations in future studies.
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24Song, C.; Knöpfel, T. Optogenetics Enlightens Neuroscience Drug Discovery. Nat. Rev. Drug Discovery 2016, 15 (2), 97– 109, DOI: 10.1038/nrd.2015.1524https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhvFalsr3L&md5=6be5793208fa21fc454812e3093e4401Optogenetics enlightens neuroscience drug discoverySong, Chenchen; Knopfel, ThomasNature Reviews Drug Discovery (2016), 15 (2), 97-109CODEN: NRDDAG; ISSN:1474-1776. (Nature Publishing Group)Optogenetics - the use of light and genetics to manipulate and monitor the activities of defined cell populations - has already had a transformative impact on basic neuroscience research. Now, the conceptual and methodol. advances assocd. with optogenetic approaches are providing fresh momentum to neuroscience drug discovery, particularly in areas that are stalled on the concept of 'fixing the brain chem.'. Optogenetics is beginning to translate and transit into drug discovery in several key domains, including target discovery, high-throughput screening and novel therapeutic approaches to disease states. Here, we discuss the exciting potential of optogenetic technologies to transform neuroscience drug discovery.
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25Hart, W. L.; Kameneva, T.; Wise, A. K.; Stoddart, P. R. Biological Considerations of Optical Interfaces for Neuromodulation. Adv. Opt. Mater. 2019, 7 (19), 1900385, DOI: 10.1002/adom.20190038525https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtlKltbjM&md5=d87c65ca500e77610bc6bce882e5791dBiological Considerations of Optical Interfaces for NeuromodulationHart, William L.; Kameneva, Tatiana; Wise, Andrew K.; Stoddart, Paul R.Advanced Optical Materials (2019), 7 (19), 1900385CODEN: AOMDAX; ISSN:2195-1071. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. The success of devices such as cochlear implants and pacemakers has led to increasing interest in new applications of artificial neural interfaces, ranging from brain-computer interfaces to vagus nerve stimulators. Both the established and emerging applications of neural interfaces have highlighted the need for improvements in spatial selectivity and reduced invasiveness, which in turn has driven growing interest in optical interfaces. The delivery of light to-and collection of light from-neural tissue presents distinct challenges for optical devices. This review presents the status of optical interface technologies with a focus on biol. considerations, such as biocompatibility, thermal loading, and tissue response. Attention is also paid to factors affecting the portability of optical interfaces, and issues around reliability and manufg. that need to be considered for successful translation. Indeed, it is imperative that engineers work closely with physiologists, clinicians, and patients when developing devices for research and the clinic. Finally, emerging trends and the potential for new technologies to disrupt the field are discussed. While many engineering challenges remain to be overcome, the achievements to date suggest that optical neuromodulation techniques have significant potential to be deployed in future for a wide range of practical therapeutic applications.
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26Zimmerman, J. F.; Tian, B. Nongenetic Optical Methods for Measuring and Modulating Neuronal Response. ACS Nano 2018, 12 (5), 4086– 4095, DOI: 10.1021/acsnano.8b0275826https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXovVamsLw%253D&md5=020982a009a2feab47a93f23f4b54bb8Nongenetic Optical Methods for Measuring and Modulating Neuronal ResponseZimmerman, John F.; Tian, BozhiACS Nano (2018), 12 (5), 4086-4095CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. The ability to probe and modulate elec. signals sensitively at cellular length scales is a key challenge in the field of electrophysiol. Elec. signals play integral roles in regulating cellular behavior and in controlling biol. function. From cardiac arrhythmias to neurodegenerative disorders, maladaptive phenotypes in electrophysiol. can result in serious and potentially deadly medical conditions. Understanding how to monitor and to control these behaviors precisely and noninvasively represents an important step in developing next-generation therapeutic devices. As the authors develop a deeper understanding of neural network formation, electrophysiol. has the potential to offer fundamental insights into the inner working of the brain. In this Perspective, the authors explore traditional methods for examg. neural function, discuss recent genetic advances in electrophysiol., and then focus on the latest innovations in optical sensing and stimulation of action potentials in neurons. The authors emphasize nongenetic optical methods, as these provide high spatiotemporal resoln. and can be achieved with minimal invasiveness.
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27Lin, Y.; Fang, Y.; Yue, J.; Tian, B. Soft-Hard Composites for Bioelectric Interfaces. Trends Chem. 2020, 2 (6), 519– 534, DOI: 10.1016/j.trechm.2020.03.00527https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhslejsLvN&md5=39c7c7164ac25f1f636b3d3d7d2018faSoft-Hard Composites for Bioelectric InterfacesLin, Yiliang; Fang, Yin; Yue, Jiping; Tian, BozhiTrends in Chemistry (2020), 2 (6), 519-534CODEN: TCRHBQ; ISSN:2589-5974. (Cell Press)A review. Bioelec. devices can probe fundamental biol. dynamics and improve the lives of human beings. However, direct application of traditional rigid electronics onto soft tissues can cause signal transduction and biocompatibility issues. One common mitigation strategy is the use of soft-hard composites to form more biocompatible interfaces with target cells or tissues. Here, we identify several soft-hard composite designs in naturally occurring systems. We use these designs to categorize the existing bioelec. interfaces and to suggest future opportunities. We discuss the utility of soft-hard composites for a variety of interfaces, such as in vitro and in vivo electronic or optoelectronic sensing and genetic and nongenetic modulation. We end the review by proposing new soft-hard composites for future bioelec. studies.
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28Medagoda, D. I.; Ghezzi, D. Organic Semiconductors for Light-Mediated Neuromodulation. Commun. Mater. 2021, 2 (1), 111, DOI: 10.1038/s43246-021-00217-z28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XotVCrsrk%253D&md5=16c961713cef4c0811f7476be34c1412Organic semiconductors for light-mediated neuromodulationMedagoda, Danashi Imani; Ghezzi, DiegoCommunications Materials (2021), 2 (1), 111CODEN: CMOAGE; ISSN:2662-4443. (Nature Portfolio)A review. Org. semiconductors have generated substantial interest in neurotechnol. and emerged as a promising approach for wireless neuromodulation in fundamental and applied research. Here, we summarise the range of applications that have been proposed so far, including retinal stimulation, excitation and inhibition of cultured neurons and regulation of biol. processes in other non-excitable cells from animal and plant origins. We also discuss the key chem. and phys. phenomena at the basis of the interaction between materials and cells. Finally, we provide an overview of future perspectives, exciting research opportunities and the remaining challenges hampering the translation of this blooming technol. into the clinic and industry.
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29Maya-Vetencourt, J. F.; Manfredi, G.; Mete, M.; Colombo, E.; Bramini, M.; Di Marco, S.; Shmal, D.; Mantero, G.; Dipalo, M.; Rocchi, A.; DiFrancesco, M. L.; Papaleo, E. D.; Russo, A.; Barsotti, J.; Eleftheriou, C.; Di Maria, F.; Cossu, V.; Piazza, F.; Emionite, L.; Ticconi, F.; Marini, C.; Sambuceti, G.; Pertile, G.; Lanzani, G.; Benfenati, F. Subretinally Injected Semiconducting Polymer Nanoparticles Rescue Vision in a Rat Model of Retinal Dystrophy. Nat. Nanotechnol. 2020, 15 (8), 698– 708, DOI: 10.1038/s41565-020-0696-329https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXht1Ontr3J&md5=714b031184a9b41207eb2b65b3bb02bdSubretinally injected semiconducting polymer nanoparticles rescue vision in a rat model of retinal dystrophyMaya-Vetencourt, Jose Fernando; Manfredi, Giovanni; Mete, Maurizio; Colombo, Elisabetta; Bramini, Mattia; Di Marco, Stefano; Shmal, Dmytro; Mantero, Giulia; Dipalo, Michele; Rocchi, Anna; DiFrancesco, Mattia L.; Papaleo, Ermanno D.; Russo, Angela; Barsotti, Jonathan; Eleftheriou, Cyril; Di Maria, Francesca; Cossu, Vanessa; Piazza, Fabio; Emionite, Laura; Ticconi, Flavia; Marini, Cecilia; Sambuceti, Gianmario; Pertile, Grazia; Lanzani, Guglielmo; Benfenati, FabioNature Nanotechnology (2020), 15 (8), 698-708CODEN: NNAABX; ISSN:1748-3387. (Nature Research)Abstr.: Inherited retinal dystrophies and late-stage age-related macular degeneration, for which treatments remain limited, are among the most prevalent causes of legal blindness. Retinal prostheses have been developed to stimulate the inner retinal network; however, lack of sensitivity and resoln., and the need for wiring or external cameras, have limited their application. Here we show that conjugated polymer nanoparticles (P3HT NPs) mediate light-evoked stimulation of retinal neurons and persistently rescue visual functions when subretinally injected in a rat model of retinitis pigmentosa. P3HT NPs spread out over the entire subretinal space and promote light-dependent activation of spared inner retinal neurons, recovering subcortical, cortical and behavioral visual responses in the absence of trophic effects or retinal inflammation. By conferring sustained light sensitivity to degenerate retinas after a single injection, and with the potential for high spatial resoln., P3HT NPs provide a new avenue in retinal prosthetics with potential applications not only in retinitis pigmentosa, but also in age-related macular degeneration.
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30Lorach, H.; Goetz, G.; Smith, R.; Lei, X.; Mandel, Y.; Kamins, T.; Mathieson, K.; Huie, P.; Harris, J.; Sher, A.; Palanker, D. Photovoltaic Restoration of Sight with High Visual Acuity. Nat. Med. 2015, 21 (5), 476– 482, DOI: 10.1038/nm.385130https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXnvFWjsrw%253D&md5=f7d079a8350f252a55cccd97ae318766Photovoltaic restoration of sight with high visual acuityLorach, Henri; Goetz, Georges; Smith, Richard; Lei, Xin; Mandel, Yossi; Kamins, Theodore; Mathieson, Keith; Huie, Philip; Harris, James; Sher, Alexander; Palanker, DanielNature Medicine (New York, NY, United States) (2015), 21 (5), 476-482CODEN: NAMEFI; ISSN:1078-8956. (Nature Publishing Group)Patients with retinal degeneration lose sight due to the gradual demise of photoreceptors. Elec. stimulation of surviving retinal neurons provides an alternative route for the delivery of visual information. We demonstrate that subretinal implants with 70-μm-wide photovoltaic pixels provide highly localized stimulation of retinal neurons in rats. The elec. receptive fields recorded in retinal ganglion cells were similar in size to the natural visual receptive fields. Similarly to normal vision, the retinal response to prosthetic stimulation exhibited flicker fusion at high frequencies, adaptation to static images and nonlinear spatial summation. In rats with retinal degeneration, these photovoltaic arrays elicited retinal responses with a spatial resoln. of 64 ± 11 μm, corresponding to half of the normal visual acuity in healthy rats. The ease of implantation of these wireless and modular arrays, combined with their high resoln., opens the door to the functional restoration of sight in patients blinded by retinal degeneration.
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31Green, M. A. Self-Consistent Optical Parameters of Intrinsic Silicon at 300 K Including Temperature Coefficients. Sol. Energy Mater. Sol. Cells 2008, 92 (11), 1305– 1310, DOI: 10.1016/j.solmat.2008.06.00931https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGksbbI&md5=767829b037109986978cb974d333b6ecSelf-consistent optical parameters of intrinsic silicon at 300 K including temperature coefficientsGreen, Martin A.Solar Energy Materials & Solar Cells (2008), 92 (11), 1305-1310CODEN: SEMCEQ; ISSN:0927-0248. (Elsevier B.V.)An updated tabulation is presented of the optical properties of intrinsic Si, of particular interest in solar cell calcns. Improved values of absorption coeff., refractive index and extinction coeff. at 300 K are tabulated over the 0.25-1.45 μm wavelength range at 0.01 μm intervals. The self-consistent tabulation was derived from Kramers-Kronig anal. of updated reflectance data deduced from the literature. The inclusion of normalized temp. coeffs. allows extrapolation over a wide temp. range, with accuracy similar to that of available exptl. data demonstrated over the -24° to 200° range.
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32Lacour, S. P.; Courtine, G.; Guck, J. Materials and Technologies for Soft Implantable Neuroprostheses. Nat. Rev. Mater. 2016, 1 (10), 16063, DOI: 10.1038/natrevmats.2016.6332https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVertLY%253D&md5=79c855fcd3ff9d92be084ee51d31a830Materials and technologies for soft implantable neuroprosthesesLacour, Stephanie P.; Courtine, Gregoire; Guck, JochenNature Reviews Materials (2016), 1 (10), 16063CODEN: NRMADL; ISSN:2058-8437. (Nature Publishing Group)Implantable neuroprostheses are engineered systems designed to restore or substitute function for individuals with neurol. deficits or disabilities. These systems involve at least one uni- or bidirectional interface between a living neural tissue and a synthetic structure, through which information in the form of electrons, ions or photons flows. Despite a few notable exceptions, the clin. dissemination of implantable neuroprostheses remains limited, because many implants display inconsistent long-term stability and performance, and are ultimately rejected by the body. Intensive research is currently being conducted to untangle the complex interplay of failure mechanisms. In this Review, we emphasize the importance of minimizing the phys. and mech. mismatch between neural tissues and implantable interfaces. We explore possible materials solns. to design and manuf. neurointegrated prostheses, and outline their immense therapeutic potential.
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33Ma, Y.; Zhang, Y.; Cai, S.; Han, Z.; Liu, X.; Wang, F.; Cao, Y.; Wang, Z.; Li, H.; Chen, Y.; Feng, X. Flexible Hybrid Electronics for Digital Healthcare. Adv. Mater. 2020, 32 (15), 1902062, DOI: 10.1002/adma.20190206233https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXht1Oqt77O&md5=908565cd01c5d117e1c0a0ba5da2a435Flexible Hybrid Electronics for Digital HealthcareMa, Yinji; Zhang, Yingchao; Cai, Shisheng; Han, Zhiyuan; Liu, Xin; Wang, Fengle; Cao, Yu; Wang, Zhouheng; Li, Hangfei; Chen, Yihao; Feng, XueAdvanced Materials (Weinheim, Germany) (2020), 32 (15), 1902062CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Recent advances in material innovation and structural design provide routes to flexible hybrid electronics that can combine the high-performance elec. properties of conventional wafer-based electronics with the ability to be stretched, bent, and twisted to arbitrary shapes, revolutionizing the transformation of traditional healthcare to digital healthcare. Here, material innovation and structural design for the prepn. of flexible hybrid electronics are reviewed, a brief chronol. of these advances is given, and biomedical applications in bioelec. monitoring and stimulation, optical monitoring and treatment, acoustic imitation and monitoring, bionic touch, and body-fluid testing are described. In conclusion, some remarks on the challenges for future research of flexible hybrid electronics are presented.
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34Han, M.; Yildiz, E.; Kaleli, H. N.; Karaz, S.; Eren, G. O.; Dogru-Yuksel, I. B.; Senses, E.; Şahin, A.; Nizamoglu, S. Tissue-Like Optoelectronic Neural Interface Enabled by PEDOT:PSS Hydrogel for Cardiac and Neural Stimulation. Adv. Healthc. Mater. 2022, 2102160, DOI: 10.1002/adhm.20210216034https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XpvFKnsg%253D%253D&md5=8d238bcc3ec4736665a8d788e6283dc0Tissue-Like Optoelectronic Neural Interface Enabled by PEDOT:PSS Hydrogel for Cardiac and Neural StimulationHan, Mertcan; Yildiz, Erdost; Kaleli, Huemeyra Nur; Karaz, Selcan; Eren, Guncem Ozgun; Dogru-Yuksel, Itir Bakis; Senses, Erkan; Sahin, Afsun; Nizamoglu, SedatAdvanced Healthcare Materials (2022), 11 (8), 2102160CODEN: AHMDBJ; ISSN:2192-2640. (Wiley-VCH Verlag GmbH & Co. KGaA)Optoelectronic biointerfaces have made a significant impact on modern science and technol. from understanding the mechanisms of the neurotransmission to the recovery of the vision for blinds. They are based on the cell interfaces made of org. or inorg. materials such as silicon, graphene, oxides, quantum dots, and π-conjugated polymers, which are dry and stiff unlike a cell/tissue environment. On the other side, wet and soft hydrogels have recently been started to attract significant attention for bioelectronics because of its high-level tissue-matching biomechanics and biocompatibility. However, it is challenging to obtain optimal opto-bioelectronic devices by using hydrogels requiring device, heterojunction, and hydrogel engineering. Here, an optoelectronic biointerface integrated with a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS, hydrogel that simultaneously achieves efficient, flexible, stable, biocompatible, and safe photostimulation of cells is demonstrated. Besides their interfacial tissue-like biomechanics, ≈34 kPa, and high-level biocompatibility, hydrogel-integration facilitates increase in charge injection amts. sevenfolds with an improved responsivity of 156 mA W-1, stability under mech. bending , and functional lifetime over three years. Finally, these devices enable stimulation of individual hippocampal neurons and photocontrol of beating frequency of cardiac myocytes via safe charge-balanced capacitive currents. Therefore, hydrogel-enabled optoelectronic biointerfaces hold great promise for next-generation wireless neural and cardiac implants.
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35Walling, M. A.; Novak, J. A.; Shepard, J. R. E. Quantum Dots for Live Cell and in Vivo Imaging. Int. J. Mol. Sci. 2009, 10 (2), 441– 491, DOI: 10.3390/ijms1002044135https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitFOgsrk%253D&md5=bc6902516551bd6b1f6b81f0586e6849Quantum dots for live cell and in vivo imagingWalling, Maureen A.; Novak, Jennifer A.; Shepard, Jason R. E.International Journal of Molecular Sciences (2009), 10 (2), 441-491CODEN: IJMCFK; ISSN:1422-0067. (Molecular Diversity Preservation International)A review. In the past few decades, technol. has made immeasurable strides to enable visualization, identification, and quantitation in biol. systems. Many of these technol. advancements are occurring on the nanometer scale, where multiple scientific disciplines are combining to create new materials with enhanced properties. The integration of inorg. synthetic methods with a size redn. to the nano-scale has lead to the creation of a new class of optical reporters, called quantum dots. These semiconductor quantum dot nanocrystals have emerged as an alternative to org. dyes and fluorescent proteins, and are brighter and more stable against photobleaching than std. fluorescent indicators. Quantum dots have tunable optical properties that have proved useful in a wide range of applications from multiplexed anal. such as DNA detection and cell sorting and tracking, to most recently demonstrating promise for in vivo imaging and diagnostics. This review provides an in-depth discussion of past, present, and future trends in quantum dot use with an emphasis on in vivo imaging and its related applications.
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36Jonsson, A.; Inal, S.; Uguz, L.; Williamson, A. J.; Kergoat, L.; Rivnay, J.; Khodagholy, D.; Berggren, M.; Bernard, C.; Malliaras, G. G.; Simon, D. T. Bioelectronic Neural Pixel: Chemical Stimulation and Electrical Sensing at the Same Site. Proc. Natl. Acad. Sci. U. S. A. 2016, 113 (34), 9440– 9445, DOI: 10.1073/pnas.160423111336https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtlSlsrnF&md5=f998b6dfeeb3fbdfb1a3f9874444535fBioelectronic neural pixel: Chemical stimulation and electrical sensing at the same siteJonsson, Amanda; Inal, Sahika; Uguz, llke; Williamson, Adam J.; Kergoat, Loig; Rivnay, Jonathan; Khodagholy, Dion; Berggren, Magnus; Bernard, Christophe; Malliaras, George G.; Simon, Daniel T.Proceedings of the National Academy of Sciences of the United States of America (2016), 113 (34), 9440-9445CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Local control of neuronal activity is central to many therapeutic strategies aiming to treat neurol. disorders. Arguably, the best soln. would make use of endogenous highly localized and specialized regulatory mechanisms of neuronal activity, and an ideal therapeutic technol. should sense activity and deliver endogenous mols. at the same site for the most efficient feedback regulation. Here, we address this challenge with an org. electronic multifunctional device that is capable of chem. stimulation and elec. sensing at the same site, at the single-cell scale. Conducting polymer electrodes recorded epileptiform discharges induced in mouse hippocampal prepn. The inhibitory neurotransmitter, γ-aminobutyric acid (GABA), was then actively delivered through the recording electrodes via org. electronic ion pump technol. GABA delivery stopped epileptiform activity, recorded simultaneously and colocally. This multifunctional "neural pixel" creates a range of opportunities, including implantable therapeutic devices with automated feedback, where locally recorded signals regulate local release of specific therapeutic agents.
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37Warden, M. R.; Cardin, J. A.; Deisseroth, K. Optical Neural Interfaces. Annual Review of Biomedical Engineering. 2014, 16, 103– 129, DOI: 10.1146/annurev-bioeng-071813-10473337https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsVKgt77L&md5=bb92bb550fcb7cf25637e376c09020b4Optical neural interfacesWarden, Melissa R.; Cardin, Jessica A.; Deisseroth, KarlAnnual Review of Biomedical Engineering (2014), 16 (), 103-129CODEN: ARBEF7; ISSN:1523-9829. (Annual Reviews)A review. Genetically encoded optical actuators and indicators have changed the landscape of neuroscience, enabling targetable control and readout of specific components of intact neural circuits in behaving animals. Here, we review the development of optical neural interfaces, focusing on hardware designed for optical control of neural activity, integrated optical control and elec. readout, and optical readout of population and single-cell neural activity in freely moving mammals.
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38Mickle, A. D.; Won, S. M.; Noh, K. N.; Yoon, J.; Meacham, K. W.; Xue, Y.; McIlvried, L. A.; Copits, B. A.; Samineni, V. K.; Crawford, K. E.; Kim, D. H.; Srivastava, P.; Kim, B. H.; Min, S.; Shiuan, Y.; Yun, Y.; Payne, M. A.; Zhang, J.; Jang, H.; Li, Y.; Lai, H. H.; Huang, Y.; Park, S. Il; Gereau, R. W.; Rogers, J. A. A Wireless Closed-Loop System for Optogenetic Peripheral Neuromodulation. Nature 2019, 565 (7739), 361– 365, DOI: 10.1038/s41586-018-0823-638https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXlslKms7c%253D&md5=6ee4b7dfcb8852230d785faff81ee1c0A wireless closed-loop system for optogenetic peripheral neuromodulationMickle, Aaron D.; Won, Sang Min; Noh, Kyung Nim; Yoon, Jangyeol; Meacham, Kathleen W.; Xue, Yeguang; McIlvried, Lisa A.; Copits, Bryan A.; Samineni, Vijay K.; Crawford, Kaitlyn E.; Kim, Do Hoon; Srivastava, Paulome; Kim, Bong Hoon; Min, Seunghwan; Shiuan, Young; Yun, Yeojeong; Payne, Maria A.; Zhang, Jianpeng; Jang, Hokyung; Li, Yuhang; Lai, H. Henry; Huang, Yonggang; Park, Sung-Il; Gereau, IV, Robert W.; Rogers, John A.Nature (London, United Kingdom) (2019), 565 (7739), 361-365CODEN: NATUAS; ISSN:0028-0836. (Nature Research)The fast-growing field of bioelectronic medicine aims to develop engineered systems that can relieve clin. conditions by stimulating the peripheral nervous system1-5. This type of technol. relies largely on elec. stimulation to provide neuromodulation of organ function or pain. One example is sacral nerve stimulation to treat overactive bladder, urinary incontinence and interstitial cystitis (also known as bladder pain syndrome)4,6,7. Conventional, continuous stimulation protocols, however, can cause discomfort and pain, particularly when treating symptoms that can be intermittent (for example, sudden urinary urgency)8. Direct phys. coupling of electrodes to the nerve can lead to injury and inflammation9-11. Furthermore, typical therapeutic stimulators target large nerve bundles that innervate multiple structures, resulting in a lack of organ specificity. Here we introduce a miniaturized bio-optoelectronic implant that avoids these limitations by using (1) an optical stimulation interface that exploits microscale inorg. light-emitting diodes to activate opsins; (2) a soft, high-precision biophys. sensor system that allows continuous measurements of organ function; and (3) a control module and data analytics approach that enables coordinated, closed-loop operation of the system to eliminate pathol. behaviors as they occur in real-time. In the example reported here, a soft strain gauge yields real-time information on bladder function in a rat model. Data algorithms identify pathol. behavior, and automated, closed-loop optogenetic neuromodulation of bladder sensory afferents normalizes bladder function. This all-optical scheme for neuromodulation offers chronic stability and the potential to stimulate specific cell types.
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39Wang, Y.; Zhu, H.; Yang, H.; Argall, A. D.; Luan, L.; Xie, C.; Guo, L. Nano Functional Neural Interfaces. Nano Res. 2018, 11 (10), 5065– 5106, DOI: 10.1007/s12274-018-2127-4There is no corresponding record for this reference.
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40Cogan, S. F. Neural Stimulation and Recording Electrodes. Annu. Rev. Biomed. Eng. 2008, 10 (1), 275– 309, DOI: 10.1146/annurev.bioeng.10.061807.16051840https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVGru7nE&md5=dc68b9ca9363036a7ceb7ee7b1b397f2Neural stimulation and recording electrodesCogan, Stuart F.Annual Review of Biomedical Engineering (2008), 10 (), 275-309CODEN: ARBEF7; ISSN:1523-9829. (Annual Reviews Inc.)A review. Elec. stimulation of nerve tissue and recording of neural elec. activity are the basis of emerging prostheses and treatments for spinal cord injury, stroke, sensory deficits, and neurol. disorders. An understanding of the electrochem. mechanisms underlying the behavior of neural stimulation and recording electrodes is important for the development of chronically implanted devices, particularly those employing large nos. of microelectrodes. For stimulation, materials that support charge injection by capacitive and faradaic mechanisms are available. These include titanium nitride, platinum, and iridium oxide, each with certain advantages and limitations. The use of charge-balanced waveforms and max. electrochem. potential excursions as criteria for reversible charge injection with these electrode materials are described and critiqued. Techniques for characterizing electrochem. properties relevant to stimulation and recording are described with examples of differences in the in vitro and in vivo response of electrodes.
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41Perlmutter, J. S.; Mink, J. W. Deep Brain Stimulation. Annu. Rev. Neurosci. 2006, 29 (1), 229– 257, DOI: 10.1146/annurev.neuro.29.051605.11282441https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XosVeitrw%253D&md5=5e2766e5160a19ab197e952e26befabeDeep brain stimulationPerlmutter, Joel S.; Mink, Jonathan W.Annual Review of Neuroscience (2006), 29 (), 229-257CODEN: ARNSD5; ISSN:0147-006X. (Annual Reviews Inc.)A review. Deep brain stimulation (DBS) has provided remarkable benefits for people with a variety of neurol. conditions. Stimulation of the ventral intermediate nucleus of the thalamus can dramatically relieve tremor assocd. with essential tremor or Parkinson disease (PD). Similarly, stimulation of the subthalamic nucleus or the internal segment of the globus pallidus can substantially reduce bradykinesia, rigidity, tremor, and gait difficulties in people with PD. Multiple groups are attempting to extend this mode of treatment to other conditions. Yet, the precise mechanism of action of DBS remains uncertain. Such studies have importance that extends beyond clin. therapeutics. Investigations of the mechanisms of action of DBS have the potential to clarify fundamental issues such as the functional anatomy of selected brain circuits and the relationship between activity in those circuits and behavior. Although we review relevant clin. issues, we emphasize the importance of current and future investigations on these topics.
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42Won, S. M.; Song, E.; Zhao, J.; Li, J.; Rivnay, J.; Rogers, J. A. Recent Advances in Materials, Devices, and Systems for Neural Interfaces. Adv. Mater. 2018, 30 (30), 1800534, DOI: 10.1002/adma.201800534There is no corresponding record for this reference.
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43Jiang, Y.; Tian, B. Inorganic Semiconductor Biointerfaces. Nat. Rev. Mater. 2018, 473– 490, DOI: 10.1038/s41578-018-0062-343https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3MjitFGqsw%253D%253D&md5=2fee7437035092ac17f845f8d3d5b15bInorganic semiconductor biointerfacesJiang Yuanwen; Tian BozhiNature reviews. Materials (2018), 3 (12), 473-490 ISSN:2058-8437.Biological systems respond to and communicate through biophysical cues, such as electrical, thermal, mechanical and topographical signals. However, precise tools for introducing localized physical stimuli and/or for sensing biological responses to biophysical signals with high spatiotemporal resolution are limited. Inorganic semiconductors display many relevant electrical and optical properties, and they can be fabricated into a broad spectrum of electronic and photonic devices. Inorganic semiconductor devices enable the formation of functional interfaces with biological material, ranging from proteins to whole organs. In this Review, we discuss fundamental semiconductor physics and operation principles, with a focus on their behaviour in physiological conditions, and highlight the advantages of inorganic semiconductors for the establishment of biointerfaces. We examine semiconductor device design and synthesis and discuss typical signal transduction mechanisms at bioelectronic and biophotonic interfaces for electronic and optoelectronic sensing, optoelectronic and photothermal stimulation and photoluminescent in vivo imaging of cells and tissues. Finally, we evaluate cytotoxicity and highlight possible new material components and biological targets of inorganic semiconductor devices.
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44Won, S. M.; Song, E.; Reeder, J. T.; Rogers, J. A. Emerging Modalities and Implantable Technologies for Neuromodulation. Cell 2020, 181 (1), 115– 135, DOI: 10.1016/j.cell.2020.02.05444https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXlslKksb8%253D&md5=26b121c5c5345eca9e6d0439afc26c24Emerging Modalities and Implantable Technologies for NeuromodulationWon, Sang Min; Song, Enming; Reeder, Jonathan T.; Rogers, John A.Cell (Cambridge, MA, United States) (2020), 181 (1), 115-135CODEN: CELLB5; ISSN:0092-8674. (Cell Press)A review. Techniques for neuromodulation serve as effective routes to care of patients with many types of challenging conditions. Continued progress in this field of medicine will require (1) improvements in our understanding of the mechanisms of neural control over organ function and (2) advances in technologies for precisely modulating these functions in a programmable manner. This review presents recent research on devices that are relevant to both of these goals, with an emphasis on multimodal operation, miniaturized dimensions, biocompatible designs, advanced neural interface schemes, and battery-free, wireless capabilities. A future that involves recording and modulating neural activity with such systems, including those that exploit closed-loop strategies and/or bioresorbable designs, seems increasingly within reach.
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45Tian, B.; Xu, S.; Rogers, J. A; Cestellos-Blanco, S.; Yang, P.; Carvalho-de-Souza, J. L; Bezanilla, F.; Liu, J.; Bao, Z.; Hjort, M. Roadmap on Semiconductor - Cell Biointerfaces. Phys. Biol. 2018, 15 (3), 031002, DOI: 10.1088/1478-3975/aa9f3445https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXkvFeksL8%253D&md5=eab786d8a3417aaf859b2082f2e82b9aRoadmap on semiconductor-cell biointerfacesTian, Bozhi; Xu, Shuai; Rogers, John A.; Cestellos-Blanco, Stefano; Yang, Peidong; Carvalho-de-Souza, Joao L.; Bezanilla, Francisco; Liu, Jia; Bao, Zhenan; Hjort, Martin; Cao, Yuhong; Melosh, Nicholas; Lanzani, Guglielmo; Benfenati, Fabio; Galli, Giulia; Gygi, Francois; Kautz, Rylan; Gorodetsky, Alon A.; Kim, Samuel S.; Lu, Timothy K.; Anikeeva, Polina; Cifra, Michal; Krivosudsky, Ondrej; Havelka, Daniel; Jiang, YuanwenPhysical Biology (2018), 15 (3), 031002/1-031002/32CODEN: PBHIAT; ISSN:1478-3975. (IOP Publishing Ltd.)A review. This roadmap outlines the role semiconductor-based materials play in understanding the complex biophys. dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mech. devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biol. components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biol. world.
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46Ekimov, A.; Onushchenko, A. Quantum Size Effect in Three-Dimensional Microscopic Semiconductor Crystals. JETP Lett. 1981, 34 (6), 345– 349There is no corresponding record for this reference.
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47Efros, A. L.; Efros, A. L. Interband Absorption of Light in a Semiconductor Sphere. Sov. Phys. Semicond. 1982, 16 (7), 772– 775There is no corresponding record for this reference.
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48Brus, L. E. A Simple Model for the Ionization Potential, Electron Affinity, and Aqueous Redox Potentials of Small Semiconductor Crystallites. J. Chem. Phys. 1983, 79 (11), 5566– 5571, DOI: 10.1063/1.44567648https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXhsF2ktw%253D%253D&md5=b0786ee952dcd7d2e759eacc7f20807fA simple model for the ionization potential, electron affinity, and aqueous redox potentials of small semiconductor crystallitesBrus, L. E.Journal of Chemical Physics (1983), 79 (11), 5566-71CODEN: JCPSA6; ISSN:0021-9606.Large semiconductor crystals have intrinsic electronic properties dependent upon the bulk band structure. As the crystal becomes small, a new regime is entered in which the electronic properties (excited states, ionization potential, electron affinity) should be strongly dependent upon the crystallite size and shape. These effects reflect quantized motion of the electron and hole in a confined space. The author addresses the possibility of a shift in the photochem. redox potential of one carrier, as a function of crystallite size. As a semiquant. guide, one might expect a shift on the order of h2/8em*R2 due to the kinetic energy of localization in the small crystallite. The elementary quantum mechanics of a charge crystallite was modeled using (1) the effective-mass approxn., (2) an electrostatic potential for dielec. polarization, and (3) penetration of the carrier outside the crystallite in the cases of small effective mass. Shifts of several tenths of an eV appear possible in crystallites of diam. 50 A. The carrier charge d. resides near the srystallite surface if the effective mass is very small.
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49Brus, L. E. Electron-Electron and Electron-Hole Interactions in Small Semiconductor Crystallites: The Size Dependence of the Lowest Excited Electronic State. J. Chem. Phys. 1984, 80 (9), 4403– 4409, DOI: 10.1063/1.44721849https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2cXitF2ltL8%253D&md5=9c2f22ebeefa7839f8c38538c6a0bc0cElectron-electron and electron-hole interactions in small semiconductor crystallites: the size dependence of the lowest excited electronic stateBrus, L. E.Journal of Chemical Physics (1984), 80 (9), 4403-9CODEN: JCPSA6; ISSN:0021-9606.The authors model, in an elementary way, the excited electronic states of semiconductor crystallites sufficiently small (∼50 Å diam) that the electronic properties differ from those of bulk materials. In this limit the excited states and ionization processes assume a mol.-like character. However, diffraction of bonding electrons by the periodic lattice potential remains of paramount importance in the crystallite electronic structure. The Schroedinger equation is solved at the same level of approxn. as used in the anal. of bulk cryst. electron-hole states (Wannier excitons). Kinetic energy is treated by the effective-mass approxn., and the potential energy is due to high-frequency dielec. solvation by at. core electrons. An approx. formula is given for the lowest excited electronic state energy. This expression is dependent upon bulk electronic properties and contains no adjustable parameters. The optical f no. for absorption and emission is also considered. The same model is applied to the problem of 2 conduction-band electrons in a small crystallite, to understand how the redox potential of excess electrons depends upon crystallite size.
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50Rossetti, R.; Nakahara, S.; Brus, L. E. Quantum Size Effects in the Redox Potentials, Resonance Raman Spectra, and Electronic Spectra of CdS Crystallites in Aqueous Solution. J. Chem. Phys. 1983, 79 (2), 1086– 1088, DOI: 10.1063/1.44583450https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3sXks1Witr4%253D&md5=b0e2f6417a44636d2ef5cd149717f26dQuantum size effects in the redox potentials, resonance Raman spectra, and electronic spectra of cadmium sulfide crystallites in aqueous solutionRossetti, R.; Nakahara, S.; Brus, L. E.Journal of Chemical Physics (1983), 79 (2), 1086-8CODEN: JCPSA6; ISSN:0021-9606.Size effects are reported in the excited electronic properties of small, crystallite CdS particles. The leading small size correction terms applicable to the photochem. redox potentials and lowest exciton energy are theor. modeled. The expt. involves controlled formation of CdS crystallites in aq. soln.
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51Brus, L. Electronic Wave Functions in Semiconductor Clusters: Experiment and Theory. J. Phys. Chem. 1986, 90 (12), 2555– 2560, DOI: 10.1021/j100403a00351https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL28XktFagtr0%253D&md5=480cab9cd92fd4d95d8be577a9bf7e0aElectronic wave functions in semiconductor clusters: experiment and theoryBrus, LouisJournal of Physical Chemistry (1986), 90 (12), 2555-60CODEN: JPCHAX; ISSN:0022-3654.Recent exptl. and theor. work in the size-dependent development of bulk electronic properties in semiconductor crystallites of ∼15 to several hundred are critically reviewed and discussed. Semiconducting electronic properties are explained in chem. valence terminol. These crystallites can be termed "clusters" because they are too small to have bulblike electronic wave functions even though they exhibit bulklike crystal structure. The principal exptl. evidence comes from the recent discovery that liq.-phase pptn. reactions can be controlled to make and stabilize cryst. semiconductor clusters in this size range. The cluster electronic properties can be studied optically in dil. colloidal solns. The cluster internal crystal structure is directly revealed by transmission electron microscopy. The results indicate that the approach of cluster electronic wave functions to the bulk Bloch MOs is exceedingly slow as a function of cluster size. This result can be anal. predicted in terms of the intrinsic electron delocalization present in cryst. materials with strong, directional chem. bonding.
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52Bera, D.; Qian, L.; Tseng, T. K.; Holloway, P. H. Quantum Dots and Their Multimodal Applications: A Review. Materials (Basel). 2010, 3 (4), 2260– 2345, DOI: 10.3390/ma3042260There is no corresponding record for this reference.
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53Guzelturk, B.; Martinez, P. L. H.; Zhang, Q.; Xiong, Q.; Sun, H.; Sun, X. W.; Govorov, A. O.; Demir, H. V. Excitonics of Semiconductor Quantum Dots and Wires for Lighting and Displays. Laser Photon. Rev. 2014, 8 (1), 73– 93, DOI: 10.1002/lpor.201300024There is no corresponding record for this reference.
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54Kambhampati, P. Unraveling the Structure and Dynamics of Excitons in Semiconductor Quantum Dots. Acc. Chem. Res. 2011, 44 (1), 1– 13, DOI: 10.1021/ar100042854https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXht12jurzI&md5=989710b3984767405fd6ebfad30e0a9aUnraveling the Structure and Dynamics of Excitons in Semiconductor Quantum DotsKambhampati, PatanjaliAccounts of Chemical Research (2011), 44 (1), 1-13CODEN: ACHRE4; ISSN:0001-4842. (American Chemical Society)A review. The quantum dot, one of the central materials in nanoscience, is a semiconductor crystal with a phys. size on the nanometer length scale. It is often called an artificial atom because researchers can create nanostructures which yield properties similar to those of real atoms. By virtue of having a size in between mols. and solids, the quantum dot offers a rich palette for exploring new science and developing novel technologies. Although the phys. structure of quantum dots is known, a clear understanding of the resultant electronic structure and dynamics has remained elusive. However, because the electronic structure and dynamics of the dot, the excitonics, confer its function in devices such as solar cells, lasers, LEDs, and nonclassical photon sources, a more complete understanding of these properties is crit. for device development. In this Account, the authors use colloidal CdSe dots as a test bed upon which to explore four select issues in excitonic processes in quantum dots. The authors have developed a state-resolved spectroscopic approach which has yielded precise measurements of the electronic structural dynamics of quantum dots and has made inroads toward creating a unified picture of many of the key dynamic processes in these materials. The authors focus on four main topics of longstanding interest and controversy: (i) hot exciton relaxation dynamics, (ii) multiexcitons, (iii) optical gain, and (iv) exciton-phonon coupling. Using this state-resolved approach, the authors reconcile long standing controversies related to phenomena such as exciton cooling and exciton-phonon coupling and make surprising new observations related to optical gain and multiexcitons.
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55Murray, C. B.; Norris, D. J.; Bawendi, M. G. Synthesis and Characterization of Nearly Monodisperse CdE (E = S, Se, Te) Semiconductor Nanocrystallites. J. Am. Chem. Soc. 1993, 115 (19), 8706– 8715, DOI: 10.1021/ja00072a02555https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlsV2ltL8%253D&md5=3ec5ea3e17f7d9a177fec0283ccdfb34Synthesis and characterization of nearly monodisperse CdE (E = sulfur, selenium, tellurium) semiconductor nanocrystallitesMurray, C. B.; Norris, D. J.; Bawendi, M. G.Journal of the American Chemical Society (1993), 115 (19), 8706-15CODEN: JACSAT; ISSN:0002-7863.A simple route to the prodn. of high-quality CdE (E = S, Se, Te) semiconductor nanocrystallites is presented. Crystallites from ∼12 Å to ∼115 Å in diam. with consistent crystal structure, surface derivatization, and a high degree of monodispersity are prepd. in a single reaction. The synthesis is based on the pyrolysis of organometallic reagents by injection into a hot coordinating solvent. This provides temporally discrete nucleation and permits controlled growth of macroscopic quantities of nanocrystallites. Size selective pptn. of crystallites from portions of the growth soln. isolates samples with narrow size distributions (<5% root-mean-square in diam.). High sample quality results in sharp absorption features and strong band-edge emission which is tunable with particle size and choice of material. TEM and x-ray powder diffraction in combination with computer simulations indicate bulk structural properties in crystallites as small as 20 Å in diam.
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56Peng, X.; Manna, L.; Yang, W.; Wickham, J.; Scher, E.; Kadavanich, A.; Alivisatos, A. P. Shape Control of CdSe Nanocrystals. Nature 2000, 404 (6773), 59– 61, DOI: 10.1038/3500353556https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXhvVylsrw%253D&md5=51f1ad169e1c6ed7517bf147cdd65b23Shape control of CdSe nanocrystalsPeng, Xiaogang; Manna, Uberato; Yang, Weidong; Wickham, Juanita; Scher, Erik; Kadavanich, Andreas; Allvisatos, A. P.Nature (London) (2000), 404 (6773), 59-61CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)Control of the growth kinetics of the II-VI semiconductor Cd selenide can be used to vary the shapes of the resulting particles from a nearly spherical morphol. to a rod-like one, with aspect ratios as large as ten to one. To maintain control of the growth rates surfactants of hexylphosphonic acid in trioctylphosphine oxide were used. TEM and powder x-ray diffraction confirmed the rod morphol. of the CdSe quantum rods.
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57Peng, Z. A.; Peng, X. Formation of High-Quality CdTe, CdSe, and CdS Nanocrystals Using CdO as Precursor [6]. J. Am. Chem. Soc. 2001, 123 (1), 183– 184, DOI: 10.1021/ja003633m57https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3cXos1Ckt7s%253D&md5=18a2cef890482b305ca2c694e2b27506Formation of high-quality CdTe, CdSe, and CdS nanocrystals using CdO as precursorPeng, Z. Adam; Peng, XiaogangJournal of the American Chemical Society (2001), 123 (1), 183-184CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)A reproducible one-pot synthesis for high-quality quantum rods and dots of CdTe, CdSe, and CdS was developed using CdO as Cd precursor. CdO and trioctylphosphine oxide (TOPO) were dissolved in hexylphosphonic acid (HPA) or tetradecylphosphonic acid (TDPA) at 300°, and a stock soln. of the chalcogen was added. The samples were characterized by XRD, TEM, and absorption spectroscopy. The resulting nanocrystals were almost monodisperse without any size sepn. The growth kinetics showed a pattern similar to that of the best CdSe nanocrystals grown from Cd(Me)2 (Peng, 1998).
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58Hines, M. A.; Guyot-Sionnest, P. Synthesis and Characterization of Strongly Luminescing ZnS-Capped CdSe Nanocrystals. J. Phys. Chem. 1996, 100 (2), 468– 471, DOI: 10.1021/jp953056258https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXhtVSgs7vN&md5=51d599a01b5db6c9cc3031be9f52c133Synthesis and Characterization of Strongly Luminescing ZnS-Capped CdSe NanocrystalsHines, Margaret A.; Guyot-Sionnest, PhilippeJournal of Physical Chemistry (1996), 100 (2), 468-71CODEN: JPCHAX; ISSN:0022-3654. (American Chemical Society)The synthesis is described of ZnS-capped CdSe semiconductor nanocrystals using organometallic reagents by a 2-step single-flask method. XPS, TEM and optical absorption are consistent with nanocrystals contg. a core of nearly monodisperse CdSe of 27-30 Å diam. with a ZnS capping 6 ± 3 Å thick. The ZnS capping with a higher bandgap than CdSe passivates the core crystallite removing the surface traps. The nanocrystals exhibit strong and stable band-edge luminescence with a 50% quantum yield at room temp.
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59Dabbousi, B. O.; Rodriguez-Viejo, J.; Mikulec, F. V.; Heine, J. R.; Mattoussi, H.; Ober, R.; Jensen, K. F.; Bawendi, M. G. (CdSe)ZnS Core-Shell Quantum Dots: Synthesis and Characterization of a Size Series of Highly Luminescent Nanocrystallites. J. Phys. Chem. B 1997, 101 (46), 9463– 9475, DOI: 10.1021/jp971091y59https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXmvVamtr0%253D&md5=53d4f2c8e1a9e480695a7e239cfd32c9(CdSe)ZnS Core-Shell Quantum Dots: Synthesis and Optical and Structural Characterization of a Size Series of Highly Luminescent MaterialsDabbousi, B. O.; Rodriguez-Viejo, J.; Mikulec, F. V.; Heine, J. R.; Mattoussi, H.; Ober, R.; Jensen, K. F.; Bawendi, M. G.Journal of Physical Chemistry B (1997), 101 (46), 9463-9475CODEN: JPCBFK; ISSN:1089-5647. (American Chemical Society)The synthesis is reported of highly luminescent (CdSe)ZnS composite quantum dots with CdSe cores of diam. 23-55 Å. The narrow luminescence (fwhm ≤ 40 nm) from these composite dots spans most of the visible spectrum from blue through red with quantum yields of 30-50% at room temp. These materials were characterized using a range of optical and structural techniques. Optical absorption and luminescence spectroscopies probe the effect of ZnS passivation on the electronic structure of the dots. A combination of wavelength dispersive x-ray spectroscopy, XPS, small and wide angle x-ray scattering, and TEM were used to analyze the composite dots and det. their chem. compn., av. size, size distribution, shape, and internal structure. Using a simple effective mass theory, the energy shift was modeled for the 1st excited state for (CdSe)ZnS and (CdSe)CdS dots with varying shell thickness. Finally, the authors characterize the growth of ZnS on CdSe cores and det. how the structure of the ZnS shell influences the photoluminescence properties.
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60Bansal, B.; Godefroo, S.; Hayne, M.; Medeiros-Ribeiro, G.; Moshchalkov, V. V. Extended Excitons and Compact Heliumlike Biexcitons in Type-II Quantum Dots. Phys. Rev. B - Condens. Matter Mater. Phys. 2009, 80 (20), 205317, DOI: 10.1103/PhysRevB.80.20531760https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhsFartrvF&md5=ebf281ec977fc9de47ddeaf3422bf805Extended excitons and compact heliumlike biexcitons in type-II quantum dotsBansal, Bhavtosh; Godefroo, S.; Hayne, M.; Medeiros-Ribeiro, G.; Moshchalkov, V. V.Physical Review B: Condensed Matter and Materials Physics (2009), 80 (20), 205317/1-205317/5CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The authors used magnetophotoluminescence measurements to establish that InP/GaAs quantum dots have a type-II (staggered) band alignment. The av. excitonic Bohr radius and the binding energy are 15 nm and 1.5 meV, resp. When compared to bulk InP, the excitonic binding is weaker due to the repulsive (type-II) potential at the heterointerface. The measurements are extended to over almost 6 orders of magnitude of laser excitation powers and to magnetic fields of up to 50 T the excitation power can be used to tune the av. hole occupancy of the quantum dots and hence the strength of the electron-hole binding. The diamagnetic shift coeff. drastically reduces as the quantum dot ensemble makes a gradual transition from a regime where the emission is from (hydrogenlike) two-particle excitonic states to a regime where emission from (heliumlike) four-particle biexcitonic states also becomes significant.
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61Kagan, C. R.; Lifshitz, E.; Sargent, E. H.; Talapin, D. V. Building Devices from Colloidal Quantum Dots. Science (80-.). 2016, 353 (6302), aac5523, DOI: 10.1126/science.aac5523There is no corresponding record for this reference.
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62Bareket-Keren, L.; Hanein, Y. Novel Interfaces for Light Directed Neuronal Stimulation: Advances and Challenges. Int. J. Nanomedicine 2014, 9 (SUPPL. 1), 65– 83, DOI: 10.2147/IJN.S5119362https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2cfpslegsg%253D%253D&md5=921cca87512f1a37c6cba99f214ce58dNovel interfaces for light directed neuronal stimulation: advances and challengesBareket-Keren Lilach; Hanein YaelInternational journal of nanomedicine (2014), 9 Suppl 1 (), 65-83 ISSN:.Light activation of neurons is a growing field with applications ranging from basic investigation of neuronal systems to the development of new therapeutic methods such as artificial retina. Many recent studies currently explore novel methods for optical stimulation with temporal and spatial precision. Novel materials in particular provide an opportunity to enhance contemporary approaches. Here we review recent advances towards light directed interfaces for neuronal stimulation, focusing on state-of-the-art nanoengineered devices. In particular, we highlight challenges and prospects towards improved retinal prostheses.
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63Winter, J. O.; Liu, T. Y.; Korgel, B. A.; Schmidt, C. E. Recognition Molecule Directed Interfacing between Semiconductor Quantum Dots and Nerve Cells. Adv. Mater. 2001, 13 (22), 1673– 1677, DOI: 10.1002/1521-4095(200111)13:22<1673::AID-ADMA1673>3.0.CO;2-663https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovVSiurw%253D&md5=b0093837e197bc36350f82bbae8d2390Recognition molecule directed interfacing between semiconductor quantum dots and nerve cellsWinter, Jessica O.; Liu, Timothy Y.; Korgel, Brian A.; Schmidt, Christine E.Advanced Materials (Weinheim, Germany) (2001), 13 (22), 1673-1677CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH)Two routes to interface living neurons with semiconductor quantum dots (qdots) were demonstrated. The first uses known antibody-antigen recognition, and the second, a new approach, uses peptide recognition groups. These methods target receptors on the neuron surface, localizing semiconductor-biomol. binding to the exterior of the cell. The semiconductor qdots were attached to living neurons using both antibody and peptide recognition mols. The reduced overall luminescence intensity from the peptide-coated qdots compared to the antibody labeled qdots results from primary, specific binding, and not from differing material properties of the qdots. The proposed approach represents one of the first attempts to both attach an object to the cell and establish elec. interactions, particularly at the nanometer scale. This approach meets two major challenges, such as the reproducible neuron/device interfacing which is difficult due to uncontrollable neuronal growth, and the relatively large sepn. between the cell and the device that leads to poor electronic coupling. The peptide recognition mols. provide nanometer-scale control over the targeting and sepn. distance between the qdot and the cell.
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64Goldman, E. R.; Balighian, E. D.; Mattoussi, H.; Kuno, M. K.; Mauro, J. M.; Tran, P. T.; Anderson, G. P. Avidin: A Natural Bridge for Quantum Dot-Antibody Conjugates. J. Am. Chem. Soc. 2002, 124 (22), 6378– 6382, DOI: 10.1021/ja012557064https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XjsFCmsLo%253D&md5=cea4f4124e094a8b70d4e4200d461ad1Avidin: A Natural Bridge for Quantum Dot-Antibody ConjugatesGoldman, Ellen R.; Balighian, Eric D.; Mattoussi, Hedi; Kuno, M. Kenneth; Mauro, J. Matthew; Tran, Phan T.; Anderson, George P.Journal of the American Chemical Society (2002), 124 (22), 6378-6382CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)The authors describe the prepn. and characterization of bioinorg. conjugates in which luminescent semiconductor CdSe-ZnS core-shell nanocrystal quantum dots (QDs) were coupled to antibodies through the use of an avidin bridge adsorbed to the nanocrystal surface via electrostatic self-assembly. Avidin, a highly pos. charged protein, was found to adsorb tightly to QDs modified with dihydrolipoic acid, which gives their surface a homogeneous neg. charge. QD conjugation to biotinylated antibodies subsequently is readily achieved. Fluoroimmunoassays utilizing these antibody conjugated QDs were successful in the detection of protein toxins (staphylococcal enterotoxin B, cholera toxin). QD-antibody conjugates formed in such a facile manner permit their use as a common immuno reagent, and in the development of multianalyte detection.
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65Michalet, X.; Pinaud, F. F.; Bentolila, L. A.; Tsay, J. M.; Doose, S.; Li, J. J.; Sundaresan, G.; Wu, A. M.; Gambhir, S. S.; Weiss, S. Quantum Dots for Live Cells, in Vivo Imaging, and Diagnostics. Science 2005, 307 (5709), 538– 544, DOI: 10.1126/science.110427465https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmslOhtw%253D%253D&md5=03a28864cfd8c3c4269cc9919d1eafb9Quantum Dots for Live Cells, in Vivo Imaging, and DiagnosticsMichalet, X.; Pinaud, F. F.; Bentolila, L. A.; Tsay, J. M.; Doose, S.; Li, J. J.; Sundaresan, G.; Wu, A. M.; Gambhir, S. S.; Weiss, S.Science (Washington, DC, United States) (2005), 307 (5709), 538-544CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)A review. Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biol. applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biol. Recent examples of their exptl. use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-IR emission during surgery. The new generations of qdots have far-reaching potential for the study of intracellular processes at the single-mol. level, high-resoln. cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
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66Choi, M. S.; Meshik, X.; Dutta, M.; Stroscio, M. A. Screening Effect on Electric Field Produced by Spontaneous Polarization in ZnO Quantum Dot in Electrolyte. 18th Int. Work. Comput. Electron. IWCE 2015 2015, 2, 49– 51, DOI: 10.1109/IWCE.2015.7301943There is no corresponding record for this reference.
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67Pappas, T. C.; Wickramanyake, W. M. S.; Jan, E.; Motamedi, M.; Brodwick, M.; Kotov, N. A. Nanoscale Engineering of a Cellular Interface with Semiconductor Nanoparticle Films for Photoelectric Stimulation of Neurons. Nano Lett. 2007, 7 (2), 513– 519, DOI: 10.1021/nl062513v67https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtlGku7rM&md5=4a964495da0b44af8419943bdc664a0eNanoscale Engineering of a Cellular Interface with Semiconductor Nanoparticle Films for Photoelectric Stimulation of NeuronsPappas, Todd C.; Wickramanyake, W. M. Shan; Jan, Edward; Motamedi, Massoud; Brodwick, Malcolm; Kotov, Nicholas A.Nano Letters (2007), 7 (2), 513-519CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)The remarkable optical and elec. properties of nanostructured materials are considered now as a source for a variety of biomaterials, biosensing, and cell interface applications. In this study, the authors report the first example of hybrid bionanodevice where absorption of light by thin films of quantum confined semiconductor nanoparticles of HgTe produced by the layer-by-layer assembly stimulate adherent neural cells via a sequence of photochem. and charge-transfer reactions. The authors also demonstrate an example of nanoscale engineering of the material driven by biol. functionalities.
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68Lugo, K.; Miao, X.; Rieke, F.; Lin, L. Y. Remote Switching of Cellular Activity and Cell Signaling Using Light in Conjunction with Quantum Dots. Biomed. Opt. Express 2012, 3 (3), 447, DOI: 10.1364/BOE.3.00044768https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjslOls7o%253D&md5=4ea5116f559857e00fd31cb7ce6690d2Remote switching of cellular activity and cell signaling using light in conjunction with quantum dotsLugo, Katherine; Miao, Xiaoyu; Rieke, Fred; Lin, Lih Y.Biomedical Optics Express (2012), 3 (3), 447-454CODEN: BOEICL; ISSN:2156-7085. (Optical Society of America)Stimulating cells by using light is a non-invasive technique that provides flexibility in probing different locations while minimizing unintended effects on the system. We propose a new way to make cells photosensitive without using genetic or chem. manipulation, which alters natural cells, in conjunction with Quantum Dots (QDs). Remote switching of cellular activity by optical QD excitation is demonstrated by integrating QDs with cells: CdTe QD films with prostate cancer (LnCap) cells, and CdSe QD films and probes with cortical neurons. Changes in membrane potential and ionic currents are recorded by using the patch-clamp method. Upon excitation, the ion channels in the cell membrane were activated, resulting in hyperpolarization or depolarization of the cell.
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69Bahmani Jalali, H.; Mohammadi Aria, M.; Dikbas, U. M.; Sadeghi, S.; Ganesh Kumar, B.; Sahin, M.; Kavakli, I. H.; Ow-Yang, C. W.; Nizamoglu, S. Effective Neural Photostimulation Using Indium-Based Type-II Quantum Dots. ACS Nano 2018, 12 (8), 8104– 8114, DOI: 10.1021/acsnano.8b0297669https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXhtlCnsbrL&md5=9b9b80aa422905c9d52332f020094b69Effective Neural Photostimulation Using Indium-Based Type-II Quantum DotsBahmani Jalali, Houman; Mohammadi Aria, Mohammad; Dikbas, Ugur Meric; Sadeghi, Sadra; Ganesh Kumar, Baskaran; Sahin, Mehmet; Kavakli, Ibrahim Halil; Ow-Yang, Cleva W.; Nizamoglu, SedatACS Nano (2018), 12 (8), 8104-8114CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Light-induced stimulation of neurons via photoactive surfaces offers rich opportunities for the development of therapeutic methods and high-resoln. retinal prosthetic devices. Quantum dots serve as an attractive building block for such surfaces, as they can be easily functionalized to match the biocompatibility and charge transport requirements of cell stimulation. Although indium-based colloidal quantum dots with type-I band alignment have attracted significant attention as a nontoxic alternative to cadmium-based ones, little attention has been paid to their photovoltaic potential as type-II heterostructures. Herein, we demonstrate type-II indium phosphide/zinc oxide core/shell quantum dots that are incorporated into a photoelectrode structure for neural photostimulation. This induces a hyperpolarizing bioelec. current that triggers the firing of a single neural cell at 4 μW mm-2, 26-fold lower than the ocular safety limit for continuous exposure to visible light. These findings show that nanomaterials can induce a biocompatible and effective biol. junction and can introduce a route in the use of quantum dots in photoelectrode architectures for artificial retinal prostheses.
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70Bahmani Jalali, H.; Karatum, O.; Melikov, R.; Dikbas, U. M.; Sadeghi, S.; Yildiz, E.; Dogru, I. B.; Ozgun Eren, G.; Ergun, C.; Sahin, A.; Kavakli, I. H.; Nizamoglu, S. Biocompatible Quantum Funnels for Neural Photostimulation. Nano Lett. 2019, 19 (9), 5975– 5981, DOI: 10.1021/acs.nanolett.9b0169770https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFCqtbbP&md5=e979d792b0c941e947a986b408223901Biocompatible Quantum Funnels for Neural PhotostimulationBahmani Jalali, Houman; Karatum, Onuralp; Melikov, Rustamzhon; Dikbas, Ugur Meric; Sadeghi, Sadra; Yildiz, Erdost; Dogru, Itir Bakis; Ozgun Eren, Guncem; Ergun, Cagla; Sahin, Afsun; Kavakli, Ibrahim Halil; Nizamoglu, SedatNano Letters (2019), 19 (9), 5975-5981CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Neural photostimulation has high potential to understand the working principles of complex neural networks and develop novel therapeutic methods for neurol. disorders. A key issue in the light-induced cell stimulation is the efficient conversion of light to bioelec. stimuli. In photosynthetic systems developed in millions of years by nature, the absorbed energy by the photoabsorbers is transported via nonradiative energy transfer to the reaction centers. Inspired by these systems, neural interfaces based on biocompatible quantum funnels are developed that direct the photogenerated charge carriers toward the bionanojunction for effective photostimulation. Funnels are constructed with indium-based rainbow quantum dots that are assembled in a graded energy profile. Implementation of a quantum funnel enhances the generated photoelectrochem. current 215% per unit absorbance in comparison with ungraded energy profile in a wireless and free-standing mode and facilitates optical neuromodulation of a single cell. This study indicates that the control of charge transport at nanoscale can lead to unconventional and effective neural interfaces.
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71Srivastava, S. B.; Melikov, R.; Aria, M. M.; Dikbas, U. M.; Kavakli, I. H.; Nizamoglu, S. Band Alignment Engineers Faradaic and Capacitive Photostimulation of Neurons Without Surface Modification. Phys. Rev. Appl. 2019, 11 (4), 044012, DOI: 10.1103/PhysRevApplied.11.04401271https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXpsF2msLw%253D&md5=3a3aa14bb47e3aeaaba9d3ceb47f7cedBand Alignment Engineers Faradaic and Capacitive Photostimulation of Neurons Without Surface ModificationSrivastava, Shashi Bhushan; Melikov, Rustamzhon; Aria, Mohammad Mohammadi; Dikbas, Ugur Meric; Kavakali, Ibrahim Halil; Nizamoglu, SedatPhysical Review Applied (2019), 11 (4), 044012CODEN: PRAHB2; ISSN:2331-7019. (American Physical Society)Photovoltaic substrates have attracted significant attention for neural photostimulation. The control of the Faradaic and capacitive (non-Faradaic) charge transfer mechanisms by these substrates are crit. for safe and effective neural photostimulation. We demonstrate that the intermediate layer can directly control the strength of the capacitive and Faradaic processes under physiol. conditions. To resolve the Faradaic and capacitive stimulations, we enhance photogenerated charge d. levels by incorporating PbS quantum dots into a poly(3-hexylthiophene-2,5-diyl):([6,6]-Phenyl-C61-butyric acid Me ester (P3HT:PCBM) blend. This enhancement stems from the simultaneous increase of absorption, well matched band alignment of PbS quantum dots with P3HT:PCBM, and smaller intermixed phase-sepd. domains with better homogeneity and roughness of the blend. These improvements lead to the photostimulation of neurons at a low light intensity level of 1 mW cm-2, which is within the retinal irradiance level. These findings open up an alternative approach toward superior neural prosthesis.
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72Zunger, A.; Ed, G. Semiconductor Quantum Dots; World Scientific, 1998; Vol. 23. DOI: 10.1557/S0883769400031213There is no corresponding record for this reference.
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73Winter, J. O.; Gomez, N.; Korgel, B. A.; Schmidt, C. E. Quantum Dots for Electrical Stimulation of Neural Cells. Nanobiophotonics and Biomedical Applications II 2005, 5705, 235, DOI: 10.1117/12.602363There is no corresponding record for this reference.
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74Colvin, V. L.; Alivisatos, A. P. CdSe Nanocrystals with a Dipole Moment in the First Excited State. J. Chem. Phys. 1992, 97 (1), 730– 733, DOI: 10.1063/1.46357374https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38Xlt1amtbY%253D&md5=74d470577f820d2797af76f38b35656dCadmium selenide nanocrystals with a dipole moment in the first excited stateColvin, V. L.; Alivisatos, A. P.Journal of Chemical Physics (1992), 97 (1), 730-3CODEN: JCPSA6; ISSN:0021-9606.The Stark effect was used to demonstrate that the first electronic state in CdSe nanocrystals has significant dipolar character. The Stark effect spectrum of CdSe crystallites embedded in polymethylmethacrylate at 100 K is given. The UV-visible spectra is also shown. The field dependence of the Stark effect signal is shown and exhibits quadratic behavior. The authors propose that the line shape results from a change in the dipole moment upon electronic excitation.
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75SCHULTZ, S. K. Principles of Neural Science, 4th Ed. Am. J. Psychiatry 2001, 158 (4), 662– 662, DOI: 10.1176/appi.ajp.158.4.662There is no corresponding record for this reference.
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76Chen, C.; Wu, Y.; Liu, L.; Gao, Y.; Chen, X.; Bi, W.; Chen, X.; Liu, D.; Dai, Q.; Song, H. Interfacial Engineering and Photon Downshifting of CsPbBr3 Nanocrystals for Efficient, Stable, and Colorful Vapor Phase Perovskite Solar Cells. Adv. Sci. 2019, 6 (11), 1802046, DOI: 10.1002/advs.20180204676https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3M3kslOkuw%253D%253D&md5=071477208ff5f7081d56d86edae2e657Interfacial Engineering and Photon Downshifting of CsPbBr3 Nanocrystals for Efficient, Stable, and Colorful Vapor Phase Perovskite Solar CellsChen Cong; Wu Yanjie; Liu Le; Gao Yanbo; Chen Xinfu; Bi Wenbo; Chen Xu; Liu Dali; Song Hongwei; Dai QilinAdvanced science (Weinheim, Baden-Wurttemberg, Germany) (2019), 6 (11), 1802046 ISSN:2198-3844.Photovoltaic devices employing lead halide perovskites as the photoactive layer have attracted enormous attention due to their commercialization potential. Yet, there exists challenges on the way to the practical use of perovskite solar cells (PSCs), such as light stability and current-voltage (J-V ) hysteresis. Inorganic perovskite nanocrystals (IPNCs) are promising candidates for high-performance photovoltaic devices due to their simple synthesis methods, tunable bandgap, and efficient photon downshifting effect for ultraviolet (UV) light blocking and conversion. In this work, CsPbBr3 IPNCs modification could give rise to the vapor phase and solution-processed PSCs with a power conversion efficiency (PCE) of 16.4% and 20.8%, respectively, increased by 11.6% and 5.6% compared to the control devices for more efficient UV utilization and carrier recombination suppression. As far as is known, 11.6% is the most effective enhanced factor for PSCs based on photon downshifting effect inside of devices. The CsPbBr3 layer could also significantly retard light-induced degradation, leading to the lifetime over 100 h under UV illumination for PSCs. Additionally, the modified PSCs exhibit weak hysteresis and multiple colors of fluorescence. These results shed light on the future design of combining a photon downshifting layer and carrier interfacial modification layer in the applications of perovskite optoelectronic devices.
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77Carey, G. H.; Abdelhady, A. L.; Ning, Z.; Thon, S. M.; Bakr, O. M.; Sargent, E. H. Colloidal Quantum Dot Solar Cells. Chem. Rev. 2015, 115 (23), 12732– 12763, DOI: 10.1021/acs.chemrev.5b0006377https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtVKitLzL&md5=757fcd30bf9b7fe70d44cfbd4f28e5adColloidal Quantum Dot Solar CellsCarey, Graham H.; Abdelhady, Ahmed L.; Ning, Zhijun; Thon, Susanna M.; Bakr, Osman M.; Sargent, Edward H.Chemical Reviews (Washington, DC, United States) (2015), 115 (23), 12732-12763CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)This review focuses on the application of colloidal quantum dots in photovoltaic devices. We survey the fabrication process, start to finish, addressing advances in synthesis methods, phys. and chem. materials processing procedures, quantification and improvement of optoelectronic properties, and device architecture and performance. This survey addresses the key challenges facing the field: synthesizing high-quality quantum dot solns. with ideal properties (band gap, absorption, monodispersity), converting these solns. into high-quality CQD films (with ideal quantum dot packing, surface passivation, and absorptive/conductive properties), and constructing an ideal material stack around the CQD film to maximize overall device efficiency.
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78Cho, Y.; Hou, B.; Lim, J.; Lee, S.; Pak, S.; Hong, J.; Giraud, P.; Jang, A. R.; Lee, Y. W.; Lee, J.; Jang, J. E.; Snaith, H. J.; Morris, S. M.; Sohn, J. I.; Cha, S.; Kim, J. M. Balancing Charge Carrier Transport in a Quantum Dot P-N Junction toward Hysteresis-Free High-Performance Solar Cells. ACS Energy Lett. 2018, 3 (4), 1036– 1043, DOI: 10.1021/acsenergylett.8b0013078https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXmslOns7g%253D&md5=f2477028fce82d8003a2079c4bf2dd8bBalancing Charge Carrier Transport in a Quantum Dot P-N Junction toward Hysteresis-Free High-Performance Solar CellsCho, Yuljae; Hou, Bo; Lim, Jongchul; Lee, Sanghyo; Pak, Sangyeon; Hong, John; Giraud, Paul; Jang, A.-Rang; Lee, Young-Woo; Lee, Juwon; Jang, Jae Eun; Snaith, Henry J.; Morris, Stephen M.; Sohn, Jung Inn; Cha, Seung Nam; Kim, Jong MinACS Energy Letters (2018), 3 (4), 1036-1043CODEN: AELCCP; ISSN:2380-8195. (American Chemical Society)In a quantum dot solar cell (QDSC) that has an inverted structure, the QD layers form two different junctions between the electron transport layer (ETL) and the other semiconducting QD layer. Recent work on an inverted-structure QDSC has revealed that the junction between the QD layers is the dominant junction, rather than the junction between the ETL and the QD layers, which is in contrast to the conventional wisdom. However, to date, there have been a lack of systematic studies on the role and importance of the QD heterojunction structure on the behavior of the solar cell and the resulting device performance. In this study, we have systematically controlled the structure of the QD junction to balance charge transport, which demonstrates that the position of the junction has a significant effect on the hysteresis effect, fill factor, and solar cell performance and is attributed to balanced charge transport.
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79Hong, J.; Hou, B.; Lim, J.; Pak, S.; Kim, B. S.; Cho, Y.; Lee, J.; Lee, Y. W.; Giraud, P.; Lee, S.; Park, J. B.; Morris, S. M.; Snaith, H. J.; Sohn, J. I.; Cha, S. N.; Kim, J. M. Enhanced Charge Carrier Transport Properties in Colloidal Quantum Dot Solar Cells via Organic and Inorganic Hybrid Surface Passivation. J. Mater. Chem. A 2016, 4 (48), 18769– 18775, DOI: 10.1039/C6TA06835A79https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28Xhs1CgtbvP&md5=b6050e3228151f60145c8df1b5a48787Enhanced charge carrier transport properties in colloidal quantum dot solar cells via organic and inorganic hybrid surface passivationHong, John; Hou, Bo; Lim, Jongchul; Pak, Sangyeon; Kim, Byung-Sung; Cho, Yuljae; Lee, Juwon; Lee, Young-Woo; Giraud, Paul; Lee, Sanghyo; Park, Jong Bae; Morris, Stephen M.; Snaith, Henry J.; Sohn, Jung Inn; Cha, SeungNam; Kim, Jong MinJournal of Materials Chemistry A: Materials for Energy and Sustainability (2016), 4 (48), 18769-18775CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)Colloidal quantum dots (CQDs) are extremely promising as photovoltaic materials. In particular, the tunability of their electronic band gap and cost effective synthetic procedures allow for the versatile fabrication of solar energy harvesting cells, resulting in optimal device performance. However, one of the main challenges in developing high performance quantum dot solar cells (QDSCs) is the improvement of the photo-generated charge transport and collection, which is mainly hindered by imperfect surface functionalization, such as the presence of surface electronic trap sites and the initial bulky surface ligands. Therefore, for these reasons, finding effective methods to efficiently decorate the surface of the as-prepd. CQDs with new short mol. length chem. structures so as to enhance the performance of QDSCs is highly desirable. Here, we suggest employing hybrid halide ions along with the shortest heterocyclic mol. as a robust passivation structure to eliminate surface trap sites while decreasing the charge trapping dynamics and increasing the charge extn. efficiency in CQD active layers. This hybrid ligand treatment shows a better coordination with Pb atoms within the crystal, resulting in low trap sites and a near perfect removal of the pristine initial bulky ligands, thereby achieving better cond. and film structure. Compared to halide ion-only treated cells, solar cells fabricated through this hybrid passivation method show an increase in the power conversion efficiency from 5.3% for the halide ion-treated cells to 6.8% for the hybrid-treated solar cells.
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80Gao, J.; Jeong, S.; Lin, F.; Erslev, P. T.; Semonin, O. E.; Luther, J. M.; Beard, M. C. Improvement in Carrier Transport Properties by Mild Thermal Annealing of PbS Quantum Dot Solar Cells. Appl. Phys. Lett. 2013, 102 (4), 043506, DOI: 10.1063/1.478943480https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFaisbc%253D&md5=73e83f273e4316d7dcd5b49371197281Improvement in carrier transport properties by mild thermal annealing of PbS quantum dot solar cellsGao, Jianbo; Jeong, Sohee; Lin, Feng; Erslev, Peter T.; Semonin, Octavi E.; Luther, Joseph M.; Beard, Matthew C.Applied Physics Letters (2013), 102 (4), 043506/1-043506/5CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)We studied the effect of post-deposition thermal annealing in the prepn. of PbS quantum dot solar cells. We find an optimal annealing temp. that improves the power conversion efficiency by a factor of 1.5 for different sized quantum dots with bandgaps of 1.65 and 1.27 eV. We examd. the onset of the photocurrent response and correlated that with domain grain growth and find that annealing the PbS quantum dot array at 120° causes little change in the PbS quantum dot size, bandgap, and open-circuit voltage and yet leads to an increase in the carrier transport as realized by an improved current response. We also find a decrease in the activation energy of a shallow trap, which also likely contributes to the improvement in the solar cell efficiency. (c) 2013 American Institute of Physics.
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81Brovelli, S.; Schaller, R. D.; Crooker, S. A.; García-Santamaría, F.; Chen, Y.; Viswanatha, R.; Hollingsworth, J. A.; Htoon, H.; Klimov, V. I. Nano-Engineered Electron-Hole Exchange Interaction Controls Exciton Dynamics in Core-Shell Semiconductor Nanocrystals. Nat. Commun. 2011, 2 (1), 280, DOI: 10.1038/ncomms128181https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC3MvkvFWqug%253D%253D&md5=cd156656ed94ca5ccf79b41c5063c31aNano-engineered electron-hole exchange interaction controls exciton dynamics in core-shell semiconductor nanocrystalsBrovelli S; Schaller R D; Crooker S A; Garcia-Santamaria F; Chen Y; Viswanatha R; Hollingsworth J A; Htoon H; Klimov V INature communications (2011), 2 (), 280 ISSN:.A strong electron-hole exchange interaction (EI) in semiconductor nanocrystals (NCs) gives rise to a large (up to tens of meV) splitting between optically active ('bright') and optically passive ('dark') excitons. This dark-bright splitting has a significant effect on the optical properties of band-edge excitons and leads to a pronounced temperature and magnetic field dependence of radiative decay. Here we demonstrate a nanoengineering-based approach that provides control over EI while maintaining nearly constant emission energy. We show that the dark-bright splitting can be widely tuned by controlling the electron-hole spatial overlap in core-shell CdSe/CdS NCs with a variable shell width. In thick-shell samples, the EI energy reduces to <250 μeV, which yields a material that emits with a nearly constant rate over temperatures from 1.5 to 300 K and magnetic fields up to 7 T. The EI-manipulation strategies demonstrated here are general and can be applied to other nanostructures with variable electron-hole overlap.
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82Meinardi, F.; Colombo, A.; Velizhanin, K. A.; Simonutti, R.; Lorenzon, M.; Beverina, L.; Viswanatha, R.; Klimov, V. I.; Brovelli, S. Large-Area Luminescent Solar Concentrators Based on Stokes-Shift-Engineered Nanocrystals in a Mass-Polymerized PMMA Matrix. Nat. Photonics 2014, 8 (5), 392– 399, DOI: 10.1038/nphoton.2014.5482https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXmtlWqsbg%253D&md5=cfa9667bf689b3f506ee0c26368f98efLarge-area luminescent solar concentrators based on 'Stokes-shift-engineered' nanocrystals in a mass-polymerized PMMA matrixMeinardi, Francesco; Colombo, Annalisa; Velizhanin, Kirill A.; Simonutti, Roberto; Lorenzon, Monica; Beverina, Luca; Viswanatha, Ranjani; Klimov, Victor I.; Brovelli, SergioNature Photonics (2014), 8 (5), 392-399CODEN: NPAHBY; ISSN:1749-4885. (Nature Publishing Group)Luminescent solar concentrators are cost-effective complements to semiconductor photovoltaics that can boost the output of solar cells and allow for the integration of photovoltaic-active architectural elements into buildings (for example, photovoltaic windows). Colloidal quantum dots are attractive for use in luminescent solar concentrators, but their small Stokes shift results in reabsorption losses that hinder the realization of large-area devices. Here, we use 'Stokes-shift-engineered' CdSe/CdS quantum dots with giant shells (giant quantum dots) to realize luminescent solar concentrators without reabsorption losses for device dimensions up to tens of centimeters. Monte-Carlo simulations show a 100-fold increase in efficiency using giant quantum dots compared with core-only nanocrystals. We demonstrate the feasibility of this approach by using high-optical-quality quantum dot-polymethylmethacrylate nanocomposites fabricated using a modified industrial method that preserves the light-emitting properties of giant quantum dots upon incorporation into the polymer. Study of these luminescent solar concentrators yields optical efficiencies >10% and an effective concn. factor of 4.4. These results demonstrate the significant promise of Stokes-shift-engineered quantum dots for large-area luminescent solar concentrators.
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83Karatum, O.; Eren, G. O.; Melikov, R.; Onal, A.; Ow-Yang, C. W.; Sahin, M.; Nizamoglu, S. Quantum Dot and Electron Acceptor Nano-Heterojunction for Photo-Induced Capacitive Charge-Transfer. Sci. Rep. 2021, 11 (1), 1– 9, DOI: 10.1038/s41598-021-82081-yThere is no corresponding record for this reference.
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84Kumsa, D. W.; Bhadra, N.; Hudak, E. M.; Kelley, S. C.; Untereker, D. F.; Mortimer, J. T. Electron Transfer Processes Occurring on Platinum Neural Stimulating Electrodes: A Tutorial on the i(V e) Profile. J. Neural Eng. 2016, 13 (5), 052001, DOI: 10.1088/1741-2560/13/5/05200184https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2szgtlGgtw%253D%253D&md5=0e743a4eb1a4752a9b84c128504a2d1eElectron transfer processes occurring on platinum neural stimulating electrodes: a tutorial on the i(V e) profileKumsa Doe W; Bhadra Narendra; Hudak Eric M; Kelley Shawn C; Untereker Darrel F; Mortimer J ThomasJournal of neural engineering (2016), 13 (5), 052001 ISSN:.The aim of this tutorial is to encourage members of the neuroprosthesis community to incorporate electron transfer processes into their thinking and provide them with the tools to do so when they design and work with neurostimulating devices. The focus of this article is on platinum because it is the most used electrode metal for devices in commercial use. The i(V e) profile or cyclic voltammogram contains information about electron transfer processes that can occur when the electrode-electrolyte interface, V e, is at a specific potential, and assumed to be near steady-state conditions. For the engineer/designer this means that if the potential is not in the range of a specific electron transfer process, that process cannot occur. An i(V e) profile, recorded at sweep rates greater than 0.1 mVs(-1), approximates steady-state conditions. Rapid transient potential excursions, like that seen with neural stimulation pulses, may be too fast for the reaction to occur, however, this means that if the potential is in the range of a specific electron transfer process it may occur and should be considered. The approach described here can be used to describe the thermodynamic electron transfer processes on other candidate electrode metals, e.g. stainless steel, iridium, carbon-based, etc.
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85Merrill, D. R.; Bikson, M.; Jefferys, J. G. R. Electrical Stimulation of Excitable Tissue: Design of Efficacious and Safe Protocols. J. Neurosci. Methods 2005, 141 (2), 171– 198, DOI: 10.1016/j.jneumeth.2004.10.02085https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD2M%252FjsVOkug%253D%253D&md5=a4e690038eaa8524f9fc557dfb9e43a4Electrical stimulation of excitable tissue: design of efficacious and safe protocolsMerrill Daniel R; Bikson Marom; Jefferys John G RJournal of neuroscience methods (2005), 141 (2), 171-98 ISSN:0165-0270.The physical basis for electrical stimulation of excitable tissue, as used by electrophysiological researchers and clinicians in functional electrical stimulation, is presented with emphasis on the fundamental mechanisms of charge injection at the electrode/tissue interface. Faradaic and non-Faradaic charge transfer mechanisms are presented and contrasted. An electrical model of the electrode/tissue interface is given. The physical basis for the origin of electrode potentials is given. Various methods of controlling charge delivery during pulsing are presented. Electrochemical reversibility is discussed. Commonly used electrode materials and stimulation protocols are reviewed in terms of stimulation efficacy and safety. Principles of stimulation of excitable tissue are reviewed with emphasis on efficacy and safety. Mechanisms of damage to tissue and the electrode are reviewed.
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86Kumsa, D. W.; Bhadra, N.; Hudak, E. M.; Kelley, S. C.; Untereker, D. F.; Mortimer, J. T. Electron Transfer Processes Occurring on Platinum Neural Stimulating Electrodes: A Tutorial on Thei(Ve) Profile. J. Neural Eng. 2016, 13 (5), 052001, DOI: 10.1088/1741-2560/13/5/05200186https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2szgtlGgtw%253D%253D&md5=0e743a4eb1a4752a9b84c128504a2d1eElectron transfer processes occurring on platinum neural stimulating electrodes: a tutorial on the i(V e) profileKumsa Doe W; Bhadra Narendra; Hudak Eric M; Kelley Shawn C; Untereker Darrel F; Mortimer J ThomasJournal of neural engineering (2016), 13 (5), 052001 ISSN:.The aim of this tutorial is to encourage members of the neuroprosthesis community to incorporate electron transfer processes into their thinking and provide them with the tools to do so when they design and work with neurostimulating devices. The focus of this article is on platinum because it is the most used electrode metal for devices in commercial use. The i(V e) profile or cyclic voltammogram contains information about electron transfer processes that can occur when the electrode-electrolyte interface, V e, is at a specific potential, and assumed to be near steady-state conditions. For the engineer/designer this means that if the potential is not in the range of a specific electron transfer process, that process cannot occur. An i(V e) profile, recorded at sweep rates greater than 0.1 mVs(-1), approximates steady-state conditions. Rapid transient potential excursions, like that seen with neural stimulation pulses, may be too fast for the reaction to occur, however, this means that if the potential is in the range of a specific electron transfer process it may occur and should be considered. The approach described here can be used to describe the thermodynamic electron transfer processes on other candidate electrode metals, e.g. stainless steel, iridium, carbon-based, etc.
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87Lai, B.-C.; Wu, J.-G.; Luo, S.-C. Revisiting Background Signals and the Electrochemical Windows of Au, Pt, and GC Electrodes in Biological Buffers. ACS Appl. Energy Mater. 2019, 2 (9), 6808– 6816, DOI: 10.1021/acsaem.9b0124987https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhsFKhsr7I&md5=5d4d8935b3f49ced481f325f5a69c894Revisiting Background Signals and the Electrochemical Windows of Au, Pt, and GC Electrodes in Biological BuffersLai, Bo-Chang; Wu, Jhih-Guang; Luo, Shyh-ChyangACS Applied Energy Materials (2019), 2 (9), 6808-6816CODEN: AAEMCQ; ISSN:2574-0962. (American Chemical Society)For electrochem. expts. involving biol. buffers, pH values, ions, and electrode materials play major roles in the electrochem. readout of the measurements. When conducting electrochem. expts., background signals are sometimes mixed with true signals, easily leading to a wrong interpretation of the data. These background signals are easily induced by the reactions between buffers and electrode materials. However, these background signals have rarely been studied systematically. In response to rapid developments in the field and application of bioelectrodes, the authors conducted a much-needed systematic study of these background signals and the electrochem. windows in buffers-specifically, of the electrochem. windows Au, glassy C, and Pt in three most commonly used biol. buffers, namely, Tris, HEPES, and phosphate. The authors examd. the pH effect using HCl, H2SO4, and NaOH to modulate the pH values from 6.0 to 9.0 in the three buffers. Also, through comparison of HCl and H2SO4, the authors were able to illustrate the reaction between Cl- ions and the metallic electrode. This reaction also led to clear redox peaks as background signals in cyclic voltammograms. When a high potential was applied, the formation of hydroxide was evident on the metallic electrode, which led to a clear redn. peak in cyclic voltammograms. The authors used an at. force microscope to monitor the morphol. of the electrode surface when a cyclic potential was applied. All tests were conducted in the presence of 100 mM LiClO4, which was used as the electrolytes. These characterization results yield crit. insights into electrode surface reactions, insights which are crucial for precisely interpreting electrochem. results measured in biol. buffers. This fundamental study provides comprehensive information, which is esp. helpful for the development of bioelectrode materials and bioelectronics applications.
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88Karatum, O.; Aria, M. M.; Eren, G. O.; Yildiz, E.; Melikov, R.; Srivastava, S. B.; Surme, S.; Dogru, I. B.; Bahmani Jalali, H.; Ulgut, B.; Sahin, A.; Kavakli, I. H.; Nizamoglu, S. Nanoengineering InP Quantum Dot-Based Photoactive Biointerfaces for Optical Control of Neurons. Frontiers in Neuroscience. 2021, 15, 724, DOI: 10.3389/fnins.2021.652608There is no corresponding record for this reference.
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89Massobrio, P.; Massobrio, G.; Martinoia, S. Interfacing Cultured Neurons to Microtransducers Arrays: A Review of the Neuro-Electronic Junction Models. Frontiers in Neuroscience. 2016, 10, 282, DOI: 10.3389/fnins.2016.0028289https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2s3jsVeiug%253D%253D&md5=ac4bf3a4f52bcee0d3f0bd764cff5aecInterfacing Cultured Neurons to Microtransducers Arrays: A Review of the Neuro-Electronic Junction ModelsMassobrio Paolo; Massobrio Giuseppe; Martinoia SergioFrontiers in neuroscience (2016), 10 (), 282 ISSN:1662-4548.Microtransducer arrays, both metal microelectrodes and silicon-based devices, are widely used as neural interfaces to measure, extracellularly, the electrophysiological activity of excitable cells. Starting from the pioneering works at the beginning of the 70's, improvements in manufacture methods, materials, and geometrical shape have been made. Nowadays, these devices are routinely used in different experimental conditions (both in vivo and in vitro), and for several applications ranging from basic research in neuroscience to more biomedical oriented applications. However, the use of these micro-devices deeply depends on the nature of the interface (coupling) between the cell membrane and the sensitive active surface of the microtransducer. Thus, many efforts have been oriented to improve coupling conditions. Particularly, in the latest years, two innovations related to the use of carbon nanotubes as interface material and to the development of micro-structures which can be engulfed by the cell membrane have been proposed. In this work, we review what can be simulated by using simple circuital models and what happens at the interface between the sensitive active surface of the microtransducer and the neuronal membrane of in vitro neurons. We finally focus our attention on these two novel technological solutions capable to improve the coupling between neuron and micro-nano transducer.
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90Lyu, Y.; Xie, C.; Chechetka, S. A.; Miyako, E.; Pu, K. Semiconducting Polymer Nanobioconjugates for Targeted Photothermal Activation of Neurons. J. Am. Chem. Soc. 2016, 138 (29), 9049– 9052, DOI: 10.1021/jacs.6b0519290https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFGjs7zK&md5=c7a7f85e6472a2fc3f0f54c48d1692f8Semiconducting Polymer Nanobioconjugates for Targeted Photothermal Activation of NeuronsLyu, Yan; Xie, Chen; Chechetka, Svetlana A.; Miyako, Eijiro; Pu, KanyiJournal of the American Chemical Society (2016), 138 (29), 9049-9052CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Optogenetics provides powerful means for precise control of neuronal activity; however, the requirement of transgenesis and the incapability to extend the neuron excitation window into the deep-tissue-penetrating near-IR (NIR) region partially limit its application. We herein report a potential alternative approach to optogenetics using semiconducting polymer nanobioconjugates (SPNsbc) as the photothermal nanomodulator to control the thermosensitive ion channels in neurons. SPNsbc are designed to efficiently absorb the NIR light at 808 nm and have a photothermal conversion efficiency higher than that of gold nanorods. By virtue of the fast heating capability in conjunction with the precise targeting to the thermosensitive ion channel, SPNsbc can specifically and rapidly activate the intracellular Ca2+ influx of neuronal cells in a reversible and safe manner. Our study provides an org. nanoparticle based strategy that eliminates the need for genetic transfection to remotely regulate cellular machinery.
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91Shapiro, M. G.; Homma, K.; Villarreal, S.; Richter, C. P.; Bezanilla, F. Infrared Light Excites Cells by Changing Their Electrical Capacitance. Nat. Commun. 2012, 3, 736, DOI: 10.1038/ncomms174291https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC38zhtVKlsg%253D%253D&md5=6148b65fe61a9f3e31dd4f25edf7f424Infrared light excites cells by changing their electrical capacitanceShapiro Mikhail G; Homma Kazuaki; Villarreal Sebastian; Richter Claus-Peter; Bezanilla FranciscoNature communications (2012), 3 (), 736 ISSN:.Optical stimulation has enabled important advances in the study of brain function and other biological processes, and holds promise for medical applications ranging from hearing restoration to cardiac pace making. In particular, pulsed laser stimulation using infrared wavelengths >1.5 μm has therapeutic potential based on its ability to directly stimulate nerves and muscles without any genetic or chemical pre-treatment. However, the mechanism of infrared stimulation has been a mystery, hindering its path to the clinic. Here we show that infrared light excites cells through a novel, highly general electrostatic mechanism. Infrared pulses are absorbed by water, producing a rapid local increase in temperature. This heating reversibly alters the electrical capacitance of the plasma membrane, depolarizing the target cell. This mechanism is fully reversible and requires only the most basic properties of cell membranes. Our findings underscore the generality of pulsed infrared stimulation and its medical potential.
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92Wang, L. V.; Hu, S. Photoacoustic Tomography: In Vivo Imaging from Organelles to Organs. Science (80-.). 2012, 335 (6075), 1458– 1462, DOI: 10.1126/science.121621092https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XktFWktrw%253D&md5=667dfb771b1bed8da79f60f354b0c988Photoacoustic Tomography: In Vivo Imaging from Organelles to OrgansWang, Lihong V.; Hu, SongScience (Washington, DC, United States) (2012), 335 (6075), 1458-1462CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Photoacoustic tomog. (PAT) can create multiscale multicontrast images of living biol. structures ranging from organelles to organs. This emerging technol. overcomes the high degree of scattering of optical photons in biol. tissue by making use of the photoacoustic effect. Light absorption by mols. creates a thermally induced pressure jump that launches ultrasonic waves, which are received by acoustic detectors to form images. Different implementations of PAT allow the spatial resoln. to be scaled with the desired imaging depth in tissue while a high depth-to-resoln. ratio is maintained. As a rule of thumb, the achievable spatial resoln. is on the order of 1/200 of the desired imaging depth, which can reach up to 7 cm. PAT provides anatomical, functional, metabolic, mol., and genetic contrasts of vasculature, hemodynamics, oxygen metab., biomarkers, and gene expression. We review the state of the art of PAT for both biol. and clin. studies and discuss future prospects.
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93Jiang, Y.; Carvalho-De-Souza, J. L.; Wong, R. C. S.; Luo, Z.; Isheim, D.; Zuo, X.; Nicholls, A. W.; Jung, I. W.; Yue, J.; Liu, D. J.; Wang, Y.; De Andrade, V.; Xiao, X.; Navrazhnykh, L.; Weiss, D. E.; Wu, X.; Seidman, D. N.; Bezanilla, F.; Tian, B. Heterogeneous Silicon Mesostructures for Lipid-Supported Bioelectric Interfaces. Nat. Mater. 2016, 15 (9), 1023– 1030, DOI: 10.1038/nmat467393https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtVKhsrfE&md5=9e770976afe38388e12fece2f94b0396Heterogeneous silicon mesostructures for lipid-supported bioelectric interfacesJiang, Yuanwen; Carvalho-de-Souza, Joao L.; Wong, Raymond C. S.; Luo, Zhiqiang; Isheim, Dieter; Zuo, Xiaobing; Nicholls, Alan W.; Jung, Il Woong; Yue, Jiping; Liu, Di-Jia; Wang, Yucai; De Andrade, Vincent; Xiao, Xianghui; Navrazhnykh, Luizetta; Weiss, Dara E.; Wu, Xiaoyang; Seidman, David N.; Bezanilla, Francisco; Tian, BozhiNature Materials (2016), 15 (9), 1023-1030CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)Silicon-based materials have widespread application as biophys. tools and biomedical devices. Here the authors introduce a biocompatible and degradable mesostructured form of silicon with multi-scale structural and chem. heterogeneities. The material was synthesized using mesoporous silica as a template through a CVD process. It has an amorphous at. structure, an ordered nanowire-based framework and random submicrometer voids, and shows an av. Young's modulus that is 2-3 orders of magnitude smaller than that of single-cryst. silicon. In addn., the authors used the heterogeneous silicon mesostructures to design a lipid-bilayer-supported bioelec. interface that is remotely controlled and temporally transient, and that permits non-genetic and subcellular optical modulation of the electrophysiol. dynamics in single dorsal root ganglia neurons. The authors' findings suggest that the biomimetic expansion of silicon into heterogeneous and deformable forms can open up opportunities in extracellular biomaterial or bioelec. systems.
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94Carvalho-de-Souza, J. L.; Treger, J. S.; Dang, B.; Kent, S. B. H.; Pepperberg, D. R.; Bezanilla, F. Photosensitivity of Neurons Enabled by Cell-Targeted Gold Nanoparticles. Neuron 2015, 86 (1), 207– 217, DOI: 10.1016/j.neuron.2015.02.03394https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksVaisrY%253D&md5=bfcc67e0facd325061fbd58fd45cbad3Photosensitivity of Neurons Enabled by Cell-Targeted Gold NanoparticlesCarvalho-de-Souza, Joao L.; Treger, Jeremy S.; Dang, Bobo; Kent, Stephen B. H.; Pepperberg, David R.; Bezanilla, FranciscoNeuron (2015), 86 (1), 207-217CODEN: NERNET; ISSN:0896-6273. (Cell Press)Unmodified neurons can be directly stimulated with light to produce action potentials, but such techniques have lacked localization of the delivered light energy. Here we show that gold nanoparticles can be conjugated to high-avidity ligands for a variety of cellular targets. Once bound to a neuron, these particles transduce millisecond pulses of light into heat, which changes membrane capacitance, depolarizing the cell and eliciting action potentials. Compared to non-functionalized nanoparticles, ligand-conjugated nanoparticles highly resist convective washout and enable photothermal stimulation with lower delivered energy and resulting temp. increase. Ligands targeting three different membrane proteins were tested; all showed similar activity and washout resistance. This suggests that many types of ligands can be bound to nanoparticles, preserving ligand and nanoparticle function, and that many different cell phenotypes can be targeted by appropriate choice of ligand. The findings have applications as an alternative to optogenetics and potentially for therapies involving neuronal photostimulation.
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95Rastogi, S. K.; Garg, R.; Scopelliti, M. G.; Pinto, B. I.; Hartung, J. E.; Kim, S.; Murphey, C. G. E.; Johnson, N.; San Roman, D.; Bezanilla, F. Remote Nongenetic Optical Modulation of Neuronal Activity Using Fuzzy Graphene. Proc. Natl. Acad. Sci. U. S. A. 2020, 117 (24), 13339– 13349, DOI: 10.1073/pnas.191992111795https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtF2jtL7I&md5=ef088ad3a31790b61f3e002e6bf67ee6Remote nongenetic optical modulation of neuronal activity using fuzzy grapheneRastogi, Sahil K.; Garg, Raghav; Scopelliti, Matteo Giuseppe; Pinto, Bernardo I.; Hartung, Jane E.; Kim, Seokhyoung; Murphey, Corban G. E.; Johnson, Nicholas; Roman, Daniel San; Bezanilla, Francisco; Cahoon, James F.; Gold, Michael S.; Chamanzar, Maysam; Cohen-Karni, TzahiProceedings of the National Academy of Sciences of the United States of America (2020), 117 (24), 13339-13349CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The ability to modulate cellular electrophysiol. is fundamental to the investigation of development, function, and disease. Currently, there is a need for remote, nongenetic, light-induced control of cellular activity in two-dimensional (2D) and three-dimensional (3D) platforms. Here, we report a breakthrough hybrid nanomaterial for remote, nongenetic, photothermal stimulation of 2D and 3D neural cellular systems. We combine one-dimensional (1D) nanowires (NWs) and 2D graphene flakes grown out-of-plane for highly controlled photothermal stimulation at subcellular precision without the need for genetic modification, with laser energies lower than a hundred nanojoules, one to two orders of magnitude lower than Au-, C-, and Si-based nanomaterials. Photothermal stimulation using NW-templated 3D fuzzy graphene (NT-3DFG) is flexible due to its broadband absorption and does not generate cellular stress. Therefore, it serves as a powerful toolset for studies of cell signaling within and between tissues and can enable therapeutic interventions.
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96Martino, N.; Feyen, P.; Porro, M.; Bossio, C.; Zucchetti, E.; Ghezzi, D.; Benfenati, F.; Lanzani, G.; Antognazza, M. R. Photothermal Cellular Stimulation in Functional Bio-Polymer Interfaces. Sci. Rep. 2015, 5, 1– 8, DOI: 10.1038/srep08911There is no corresponding record for this reference.
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97Jiang, Y.; Lee, H. J.; Lan, L.; Tseng, H. an; Yang, C.; Man, H. Y.; Han, X.; Cheng, J. X. Optoacoustic Brain Stimulation at Submillimeter Spatial Precision. Nat. Commun. 2020, 11 (1), 1– 9, DOI: 10.1038/s41467-020-14706-1There is no corresponding record for this reference.
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98Shi, L.; Jiang, Y.; Fernandez, F. R.; Chen, G.; Lan, L.; Man, H.-Y.; White, J. A.; Cheng, J.-X.; Yang, C. Non-Genetic Photoacoustic Stimulation of Single Neurons by a Tapered Fiber Optoacoustic Emitter. Light Sci. Appl. 2021, 10 (1), 143, DOI: 10.1038/s41377-021-00580-z98https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhsFGgt7bF&md5=9a9ba0e6c81f5152e368e74f26aa16a8Non-genetic photoacoustic stimulation of single neurons by a tapered fiber optoacoustic emitterShi, Linli; Jiang, Ying; Fernandez, Fernando R.; Chen, Guo; Lan, Lu; Man, Heng-Ye; White, John A.; Cheng, Ji-Xin; Yang, ChenLight: Science & Applications (2021), 10 (1), 143CODEN: LSAIAZ; ISSN:2047-7538. (Nature Research)Abstr.: Neuromodulation at high spatial resoln. poses great significance in advancing fundamental knowledge in the field of neuroscience and offering novel clin. treatments. Here, we developed a tapered fiber optoacoustic emitter (TFOE) generating an ultrasound field with a high spatial precision of 39.6 μm, enabling optoacoustic activation of single neurons or subcellular structures, such as axons and dendrites. Temporally, a single acoustic pulse of sub-microsecond converted by the TFOE from a single laser pulse of 3 ns is shown as the shortest acoustic stimuli so far for successful neuron activation. The precise ultrasound generated by the TFOE enabled the integration of the optoacoustic stimulation with highly stable patch-clamp recording on single neurons. Direct measurements of the elec. response of single neurons to acoustic stimulation, which is difficult for conventional ultrasound stimulation, have been demonstrated. By coupling TFOE with ex vivo brain slice electrophysiol., we unveil cell-type-specific responses of excitatory and inhibitory neurons to acoustic stimulation. These results demonstrate that TFOE is a non-genetic single-cell and sub-cellular modulation technol., which could shed new insights into the mechanism of ultrasound neurostimulation.
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99Tao, W.; Ji, X.; Xu, X.; Islam, M. A.; Li, Z.; Chen, S.; Saw, P. E.; Zhang, H.; Bharwani, Z.; Guo, Z.; Shi, J.; Farokhzad, O. C. Antimonene Quantum Dots: Synthesis and Application as Near-Infrared Photothermal Agents for Effective Cancer Therapy. Angew. Chemie Int. Ed. 2017, 56 (39), 11896– 11900, DOI: 10.1002/anie.20170365799https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtFOlt7bN&md5=1fa6db1268d20d3e07d4553cb69e896cAntimonene quantum dots: Synthesis and application as near-infrared photothermal agents for effective cancer therapyTao, Wei; Ji, Xiaoyuan; Xu, Xiaoding; Islam, Mohammad Ariful; Li, Zhongjun; Chen, Si; Saw, Phei Er; Zhang, Han; Bharwani, Zameer; Guo, Zilei; Shi, Jinjun; Farokhzad, Omid C.Angewandte Chemie, International Edition (2017), 56 (39), 11896-11900CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)Photothermal therapy (PTT) has shown significant potential for cancer therapy. However, developing nanomaterials (NMs)-based photothermal agents (PTAs) with satisfactory photothermal conversion efficacy (PTCE) and biocompatibility remains a key challenge. Herein, a new generation of PTAs based on two-dimensional (2D) antimonene quantum dots (AMQDs) was developed by a novel liq. exfoliation method. Surface modification of AMQDs with polyethylene glycol (PEG) significantly enhanced both biocompatibility and stability in physiol. medium. The PEG-coated AMQDs showed a PTCE of 45.5 %, which is higher than many other NMs-based PTAs such as graphene, Au, MoS2, and black phosphorus (BP). The AMQDs-based PTAs also exhibited a unique feature of NIR-induced rapid degradability. Through both in vitro and in vivo studies, the PEG-coated AMQDs demonstrated notable NIR-induced tumor ablation ability. This work is expected to expand the utility of 2D antimonene (AM) to biomedical applications through the development of an entirely novel PTA platform.
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100Guo, T.; Tang, Q.; Guo, Y.; Qiu, H.; Dai, J.; Xing, C.; Zhuang, S.; Huang, G. Boron Quantum Dots for Photoacoustic Imaging-Guided Photothermal Therapy. ACS Appl. Mater. Interfaces 2021, 13 (1), 306– 311, DOI: 10.1021/acsami.0c21198100https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtVyjuw%253D%253D&md5=30d8cda970e60c6d13add1fe507e3c3cBoron Quantum Dots for Photoacoustic Imaging-Guided Photothermal TherapyGuo, Tao; Tang, Qiuyu; Guo, Yating; Qiu, Honglong; Dai, Jing; Xing, Chao; Zhuang, Shihao; Huang, GuomingACS Applied Materials & Interfaces (2021), 13 (1), 306-311CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Photothermal therapy is a new type of tumor therapy with great potential. An ideal photothermal therapy agent should have high photothermal conversion effect, low biol. toxicity, and degradability. The development of novel photothermal therapy agents with these properties is of great demand. In this study, we synthesized boron quantum dots (BQDs) with an ultrasmall hydrodynamic diam. Both in vitro and in vivo studies show that the as-synthesized BQDs have good biol. safety, high photoacoustic imaging performance, and photothermal conversion ability, which can be used for photoacoustic imaging-guided photothermal agents for tumor treatment. Our investigations confirm that the BQDs hold great promise in tumor theranostic applications.
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101Srivastava, S. B.; Melikov, R.; Yildiz, E.; Han, M.; Sahin, A.; Nizamoglu, S. Efficient Photocapacitors via Ternary Hybrid Photovoltaic Optimization for Photostimulation of Neurons. Biomed. Opt. Express 2020, 11 (9), 5237, DOI: 10.1364/BOE.396068101https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXisFSrs7rI&md5=62a8d66d6b8798f5cca61e5d189b36b7Efficient photocapacitors via ternary hybrid photovoltaic optimization for photostimulation of neuronsSrivastava, Shashi Bhushan; Melikov, Rustamzhon; Yildiz, Erdost; Han, Mertcan; Sahin, Afsun; Nizamoglu, SedatBiomedical Optics Express (2020), 11 (9), 5237-5248CODEN: BOEICL; ISSN:2156-7085. (Optical Society of America)Optoelectronic photoelectrodes based on capacitive charge-transfer offer an attractive route to develop safe and effective neuromodulators. Here, we demonstrate efficient optoelectronic photoelectrodes that are based on the incorporation of quantum dots (QDs) into poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-Phenyl-C61-butyric acid Me ester (PCBM) bulk heterojunction. We control the performance of the photoelectrode by the blend ratio, thickness, and nanomorphol. of the ternary bulk heterojunction. The optimization led to a photocapacitor that has a photovoltage of 450 mV under a light intensity level of 20 mW.cm-2 and a responsivity of 99 mA/W corresponding to the most light-sensitive org. photoelectrode reported to date. The photocapacitor can facilitate action potential generation by hippocampal neurons via burst waveforms at an intensity level of 20 mW.cm-2. Therefore, the results point to an alternative direction in the engineering of safe and ultra-light-sensitive neural interfaces.
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102Han, M.; Bahmani Jalali, H.; Yildiz, E.; Qureshi, M. H.; Şahin, A.; Nizamoglu, S. Photovoltaic Neurointerface Based on Aluminum Antimonide Nanocrystals. Commun. Mater. 2021, 2 (1), 19, DOI: 10.1038/s43246-021-00123-4102https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XotVCktr4%253D&md5=cf9de0001d958294430f880cd1a090f5Photovoltaic neurointerface based on aluminum antimonide nanocrystalsHan, Mertcan; Bahmani Jalali, Houman; Yildiz, Erdost; Qureshi, Mohammad Haroon; Sahin, Afsun; Nizamoglu, SedatCommunications Materials (2021), 2 (1), 19CODEN: CMOAGE; ISSN:2662-4443. (Nature Portfolio)Light activated modulation of neural activity is an emerging field for the basic investigation of neural systems and development of new therapeutic methods such as artificial retina. Colloidal inorg. nanocrystals have great potential for neural interfaces due to their adjustable optoelectronic properties via high-level structural, compositional, and size control. However, toxic heavy metal content (e.g., cadmium, mercury), electrochem. coupling to the cells and low photon-to-current efficiency limit their effective use. Here, we introduce the use of aluminum antimonide (AlSb) nanocrystals as the cell interfacing layer for capacitive neural stimulation in the blue spectrum. We demonstrate successful photostimulation of primary hippocampal neurons below ocular safety limits. In addn., our device shows high biocompatibility in vitro and passive accelerated ageing tests indicate a functional lifetime over 3 years showing their feasible use for chronic implants. We demonstrate that nanocrystal biointerfaces hold high promise for future bioelectronics and protheses.
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103Keuleyan, S.; Kohler, J.; Guyot-Sionnest, P. Photoluminescence of Mid-Infrared HgTe Colloidal Quantum Dots. J. Phys. Chem. C 2014, 118 (5), 2749– 2753, DOI: 10.1021/jp409061g103https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXnsV2ntg%253D%253D&md5=39eca69f0eff7c324b44e1546897884aPhotoluminescence of Mid-Infrared HgTe Colloidal Quantum DotsKeuleyan, Sean; Kohler, John; Guyot-Sionnest, PhilippeJournal of Physical Chemistry C (2014), 118 (5), 2749-2753CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)The photoluminescence quantum yield of HgTe colloidal quantum dots is measured from 1800 to 6500 cm-1. There is a steep drop to low energy reminiscent of the generic gap law. However, direct evidence of energy transfer to the C-H stretch and overtone vibrations is apparent when temp. tunes the PL wavelength of a given sample through the vibrational resonances. Calcns. based on the radiative rate and resonant energy transfer to the ligand vibrations appear to account for much of the quantum yield drop. Power-dependent photoluminescence lifetime measurements on 3.7 nm particles show fast, ∼50 ps, biexciton lifetime similar to other colloidal quantum dot systems of similar sizes.
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104Keuleyan, S. E.; Guyot-Sionnest, P.; Delerue, C.; Allan, G. Mercury Telluride Colloidal Quantum Dots: Electronic Structure, Size-Dependent Spectra, and Photocurrent Detection up to 12 Μm. ACS Nano 2014, 8 (8), 8676– 8682, DOI: 10.1021/nn503805h104https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtleqt7jP&md5=4fbdd230d199457c5e20899dffd26347Mercury Telluride Colloidal Quantum Dots: Electronic Structure, Size-Dependent Spectra, and Photocurrent Detection up to 12 μmKeuleyan, Sean E.; Guyot-Sionnest, Philippe; Delerue, Christophe; Allan, GuyACS Nano (2014), 8 (8), 8676-8682CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)HgTe colloidal quantum dots are synthesized with high monodispersivity with sizes up to ∼15 nm corresponding to a room temp. absorption edge at ∼5 μm. The shape is tetrahedral for larger sizes and up to five peaks are seen in the absorption spectra with a clear size dependence. The size range of the HgTe quantum dots is extended to ∼20 nm using regrowth. The corresponding room temp. photoluminescence and absorption edge reach into the long-wave IR, past 8 μm. Upon cooling to liq. nitrogen temp., a photoconductive response is obtained in the long-wave IR region up to 12 μm. Configuration-interaction tight-binding calcns. successfully explain the spectra and the size dependence. The five optical features can be assigned to sets of single hole to single electron transitions whose strengths are strongly influenced by the multiband/multiorbital character of the quantum-dot electronic states.
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105Keuleyan, S.; Lhuillier, E.; Brajuskovic, V.; Guyot-Sionnest, P. Mid-Infrared HgTe Colloidal Quantum Dot Photodetectors. Nat. Photonics 2011, 5 (8), 489– 493, DOI: 10.1038/nphoton.2011.142105https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXpsFWmtLc%253D&md5=3de241869a3f34c4770970ccfaa3e30bMid-infrared HgTe colloidal quantum dot photodetectorsKeuleyan, Sean; Lhuillier, Emmanuel; Brajuskovic, Vuk; Guyot-Sionnest, PhilippeNature Photonics (2011), 5 (8), 489-493CODEN: NPAHBY; ISSN:1749-4885. (Nature Publishing Group)Today's IR imaging devices are based on bulk and quantum-confined epitaxial materials and would benefit greatly from higher operating temps. and lower cost. Imaging chips based on colloidal quantum dot technol. could offer a convenient lower-cost alternative, but, to date, the spectral range of operation of colloidal quantum dots has been limited. In this Letter, we report colloidal HgTe quantum dot photodetectors with a room-temp. photoresponse beyond 5 μm, the longest interband absorption wavelength reported so far for colloidal materials. The photodetectors are fabricated from colloidal solns., which are then drop-cast as thin films on electrodes. Operation covering the important atm. mid-wavelength IR transparency window between 3 and 5 μm is demonstrated.
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106Åkerman, M. E.; Chan, W. C. W.; Laakkonen, P.; Bhatia, S. N.; Ruoslahti, E. Nanocrystal Targeting in Vivo. Proc. Natl. Acad. Sci. U. S. A. 2002, 99 (20), 12617– 12621, DOI: 10.1073/pnas.152463399106https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XnvFGiu7c%253D&md5=6acdbfb5997f6cd27c27db63d1f2ba79Nanocrystal targeting in vivoAkerman, Maria E.; Chan, Warren C. W.; Laakkonen, Pirjo; Bhatia, Sangeeta N.; Ruoslahti, ErkkiProceedings of the National Academy of Sciences of the United States of America (2002), 99 (20), 12617-12621CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Inorg. nanostructures that interface with biol. systems have recently attracted widespread interest in biol. and medicine. Nanoparticles are thought to have potential as novel intravascular probes for both diagnostic (e.g., imaging) and therapeutic purposes (e.g., drug delivery). Crit. issues for successful nanoparticle delivery include the ability to target specific tissues and cell types and escape from the biol. particulate filter known as the reticuloendothelial system. We set out to explore the feasibility of in vivo targeting by using semiconductor quantum dots (qdots). Qdots are small (<10 nm) inorg. nanocrystals that possess unique luminescent properties; their fluorescence emission is stable and tuned by varying the particle size or compn. We show that ZnS-capped CdSe qdots coated with a lung-targeting peptide accumulate in the lungs of mice after i.v. injection, whereas two other peptides specifically direct qdots to blood vessels or lymphatic vessels in tumors. We also show that adding polyethylene glycol to the qdot coating prevents nonselective accumulation of qdots in reticuloendothelial tissues. These results encourage the construction of more complex nanostructures with capabilities such as disease sensing and drug delivery.
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107Larson, D. R.; Zipfel, W. R.; Williams, R. M.; Clark, S. W.; Bruchez, M. P.; Wise, F. W.; Webb, W. W. Water-Soluble Quantum Dots for Multiphoton Fluorescence Imaging in Vivo. Science (80-.). 2003, 300 (5624), 1434– 1436, DOI: 10.1126/science.1083780107https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXktFGktLc%253D&md5=a8ac89b0ae3234ec3d9f121a18d0adc5Water-soluble quantum dots for multiphoton fluorescence imaging in vivoLarson, Daniel R.; Zipfel, Warren R.; Williams, Rebecca M.; Clark, Stephen W.; Bruchez, Marcel P.; Wise, Frank W.; Webb, Watt W.Science (Washington, DC, United States) (2003), 300 (5624), 1434-1437CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)The use of semiconductor nanocrystals (quantum dots) as fluorescent labels for multiphoton microscopy enables multicolor imaging in demanding biol. environments such as living tissue. We characterized water-sol. cadmium selenide-zinc sulfide quantum dots for multiphoton imaging in live animals. These fluorescent probes have two-photon action cross sections as high as 47,000 Goeppert-Mayer units, by far the largest of any label used in multiphoton microscopy. We visualized quantum dots dynamically through the skin of living mice, in capillaries hundreds of micrometers deep. We found no evidence of blinking (fluorescence intermittency) in soln. on nanosecond to millisecond time scales.
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108Chan, W. C. W.; Nie, S. Quantum Dot Bioconjugates for Ultrasensitive Nonisotopic Detection. Science (80-.). 1998, 281 (5385), 2016– 2018, DOI: 10.1126/science.281.5385.2016108https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXmtlKnsrk%253D&md5=481c7a81438f03ca6c871d30afde6eb3Quantum dot bioconjugates for ultrasensitive nonisotopic detectionChan, Warren C. W.; Nile, ShumingScience (Washington, D. C.) (1998), 281 (5385), 2016-2018CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomols. for use in ultra-sensitive biol. detection. In comparison with org. dyes such as rhodamine, this class of luminescent labels is 20 times as bright, 100 times as stable against photobleaching, and one-third as wide in spectral linewidth. These nanometer-sized conjugates are water-sol. and biocompatible. Quantum dots that were labeled with the protein transferrin underwent receptor-mediated endocytosis in cultured HeLa cells, and those dots that were labeled with immunomols. recognized specific antibodies or antigens.
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109Parak, W. J.; Boudreau, R.; Le Gros, M.; Gerion, D.; Zanchet, D.; Micheel, C. M.; Williams, S. C.; Alivisatos, A. P.; Larabell, C. Cell Motility and Metastatic Potential Studies Based on Quantum Dot Imaging of Phagokinetic Tracks. Adv. Mater. 2002, 14 (12), 882– 885, DOI: 10.1002/1521-4095(20020618)14:12<882::AID-ADMA882>3.0.CO;2-Y109https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XltlGju7o%253D&md5=65b603bb72df34185d70a44d5bd189abCell motility and metastatic potential studies based on quantum dot imaging of phagokinetic tracksParak, Wolfgang J.; Boudreau, Rosanne; Le Gros, Mark; Gerion, Daniele; Zanchet, Daniela; Micheel, Christine M.; Williams, Shara C.; Alivisatos, A. Paul; Larabell, CarolynAdvanced Materials (Weinheim, Germany) (2002), 14 (12), 882-885CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH)The recent advances in semiconductor nanotechnol. have aided in the improvement of cell motility assays, particularly in the phagokinetic uptake of colloidal quantum dots. Thin layers of colloidal semiconductor nanocrystals were deposited on collagen-coated tissue culture substrates, followed by seeding of cells. Two types of cell lines were examd. in detail, human mammary epithelial tumor cells and non-tumor cells. The colloidal quantum dots were readily ingested by all of the cell lines examd. The degree of the nanocrystal uptake reflects the migratory behavior of the cell via a process of pino-, endo- and/or phagocytosis of the surrounding matrix. The nanocrystals readily adhere to the cell surface, most likely due to interactions of the cell surface glycoproteins and glycolipids with the nanocrystal surface. The colloidal quantum-dot based phagonkinetic tracking proved to be a versatile and powerful method of quantifying motility in a wide variety of circumstances.
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110Wu, X.; Liu, H.; Liu, J.; Haley, K. N.; Treadway, J. A.; Larson, J. P.; Ge, N.; Peale, F.; Bruchez, M. P. Immunofluorescent Labeling of Cancer Marker Her2 and Other Cellular Targets with Semiconductor Quantum Dots. Nat. Biotechnol. 2003, 21 (1), 41– 46, DOI: 10.1038/nbt764110https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhvVyl&md5=66f13dafe63f510984d5b953c59266fbImmunofluorescent labeling of cancer marker Her2 and other cellular targets with semiconductor quantum dotsWu, Xingyong; Liu, Hongjian; Liu, Jianquan; Haley, Kari N.; Treadway, Joseph A.; Larson, J. Peter; Ge, Nianfeng; Peale, Frank; Bruchez, Marcel P.Nature Biotechnology (2003), 21 (1), 41-46CODEN: NABIF9; ISSN:1087-0156. (Nature Publishing Group)Semiconductor quantum dots (QDs) are among the most promising emerging fluorescent labels for cellular imaging. However, it is unclear whether QDs, which are nanoparticles rather than small mols., can specifically and effectively label mol. targets at a subcellular level. Here we have used QDs linked to IgG (IgG) and streptavidin to label the breast cancer marker Her2 on the surface of fixed and live cancer cells, to stain actin and microtubule fibers in the cytoplasm, and to detect nuclear antigens inside the nucleus. All labeling signals are specific for the intended targets and are brighter and considerably more photostable than comparable org. dyes. Using QDs with different emission spectra conjugated to IgG and streptavidin, we simultaneously detected two cellular targets with one excitation wavelength. The results indicate that QD-based probes can be very effective in cellular imaging and offer substantial advantages over org. dyes in multiplex target detection.
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111Dahan, M.; Lévi, S.; Luccardini, C.; Rostaing, P.; Riveau, B.; Triller, A. Diffusion Dynamics of Glycine Receptors Revealed by Single-Quantum Dot Tracking. Science (80-.). 2003, 302 (5644), 442– 445, DOI: 10.1126/science.1088525There is no corresponding record for this reference.
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112Prevarskaya, N.; Skryma, R.; Bidaux, G.; Flourakis, M.; Shuba, Y. Ion Channels in Death and Differentiation of Prostate Cancer Cells. Cell Death Differ. 2007, 14 (7), 1295– 1304, DOI: 10.1038/sj.cdd.4402162112https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXms1Sqs7s%253D&md5=c15ce1972a630efb9b8fd83837c5e8d4Ion channels in death and differentiation of prostate cancer cellsPrevarskaya, N.; Skryma, R.; Bidaux, G.; Flourakis, M.; Shuba, Y.Cell Death and Differentiation (2007), 14 (7), 1295-1304CODEN: CDDIEK; ISSN:1350-9047. (Nature Publishing Group)A review. Plasma membrane ion channels contribute to virtually all basic cellular processes, including such crucial ones for maintaining tissue homeostasis as proliferation, differentiation, and apoptosis. Enhanced proliferation, aberrant differentiation, and impaired ability to die are the prime reasons for abnormal tissue growth, which can eventually turn into uncontrolled expansion and invasion, characteristic of cancer. Prostate cancer (PCa) cells express a variety of plasma membrane ion channels. By providing the influx of essential signaling ions, perturbing intracellular ion concns., regulating cell vol., and maintaining membrane potential, PCa cells are critically involved in proliferation, differentiation, and apoptosis. PCa cells of varying metastatic ability can be distinguished by their ion channel characteristics. Increased malignancy and invasiveness of androgen-independent PCa cells is generally assocd. with the shift to a 'more excitable' phenotype of their plasma membrane. This shift is manifested by the appearance of voltage-gated Na+ and Ca2+ channels which contribute to their enhanced apoptotic resistance together with down regulated store-operated Ca2+ influx, altered expression of different K+ channels and members of the Transient Receptor Potential (TRP) channel family, and strengthened capability for maintaining vol. constancy. The present review examines channel types expressed by PCa cells and their involvement in metastatic behaviors.
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113Bareket, L.; Waiskopf, N.; Rand, D.; Lubin, G.; David-Pur, M.; Ben-Dov, J.; Roy, S.; Eleftheriou, C.; Sernagor, E.; Cheshnovsky, O.; Banin, U.; Hanein, Y. Semiconductor Nanorod-Carbon Nanotube Biomimetic Films for Wire-Free Photostimulation of Blind Retinas. Nano Lett. 2014, 14 (11), 6685– 6692, DOI: 10.1021/nl5034304113https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVegu7vN&md5=45b99d5d55ba75e8878f5a4b66bb0224Semiconductor Nanorod-Carbon Nanotube Biomimetic Films for Wire-Free Photostimulation of Blind RetinasBareket, Lilach; Waiskopf, Nir; Rand, David; Lubin, Gur; David-Pur, Moshe; Ben-Dov, Jacob; Roy, Soumyendu; Eleftheriou, Cyril; Sernagor, Evelyne; Cheshnovsky, Ori; Banin, Uri; Hanein, YaelNano Letters (2014), 14 (11), 6685-6692CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)We report the development of a semiconductor nanorod-carbon nanotube based platform for wire-free, light induced retina stimulation. A plasma polymd. acrylic acid midlayer was used to achieve covalent conjugation of semiconductor nanorods directly onto neuro-adhesive, three-dimensional carbon nanotube surfaces. Photocurrent, photovoltage, and fluorescence lifetime measurements validate efficient charge transfer between the nanorods and the carbon nanotube films. Successful stimulation of a light-insensitive chick retina suggests the potential use of this novel platform in future artificial retina applications.
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114Gabay, T.; Ben-David, M.; Kalifa, I.; Sorkin, R.; Abrams, Z. R.; Ben-Jacob, E.; Hanein, Y. Electro-Chemical and Biological Properties of Carbon Nanotube Based Multi-Electrode Arrays. Nanotechnology 2007, 18 (3), 035201, DOI: 10.1088/0957-4484/18/3/035201114https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXjtFChsb8%253D&md5=996cd678dae95af94ab505c704b9d1e3Electro-chemical and biological properties of carbon nanotube based multi-electrode arraysGabay, Tamir; Ben-David, Moti; Kalifa, Itshak; Sorkin, Raya; Abrams, Ze'ev R.; Ben-Jacob, Eshel; Hanein, YaelNanotechnology (2007), 18 (3), 035201/1-035201/6CODEN: NNOTER; ISSN:0957-4484. (Institute of Physics Publishing)A novel class of micro-electrodes was fabricated by synthesizing high d. carbon nanotube islands on lithog. defined, passivated titanium nitride conductors on a silicon dioxide substrate. Electrochem. characterization in phosphate buffered saline of these new electrodes reveals superb electrochem. properties marked by featureless rectangular cyclic voltammetry curves corresponding to a DC surface specific capacitance and a vol. specific capacitance as high as 10 mF cm-2 and 10 F cm-3, resp. These electrodes are also characterized by a slowly varying impedance magnitude over the range of 1 Hz to 20 kHz. High fidelity extracellular recordings from cultured neurons were performed and analyzed to validate the effectiveness of the fabricated electrodes. The enhanced electrochem. properties of the electrodes, their flexible and simple micro-fabrication prepn. procedure as well as their bio-compatibility and durability suggest that carbon nanotube electrodes are a promising platform for high resoln. capacitive electrochem. applications.
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115Shoval, A.; Adams, C.; David-Pur, M.; Shein, M.; Hanein, Y.; Sernagor, E. Carbon Nanotube Electrodes for Effective Interfacing with Retinal Tissue. Front. Neuroeng. 2009, 2 (APR), 4, DOI: 10.3389/neuro.16.004.2009115https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXptlGitr4%253D&md5=2b0c23f595c16561b755535fd39e9589Carbon nanotube electrodes for effective interfacing with retinal tissueShoval, Asaf; Adams, Christopher; David-Pur, Moshe; Shein, Mark; Hanein, Yael; Sernagor, EvelyneFrontiers in Neuroengineering (2009), 2 (April), 4CODEN: FNREIF; ISSN:1662-6443. (Frontiers Research Foundation)We have investigated the use of carbon nanotube coated microelectrodes as an interface material for retinal recording and stimulation applications. Test devices were micro-fabricated and consisted of 60, 30 μm diam. electrodes at spacing of 200 μm. These electrodes were coated via chem. vapor deposition of carbon nanotubes, resulting in conducting, three dimensional surfaces with a high interfacial area. These attributes are important both for the quality of the cell-surface coupling as well as for electro-chem. interfacing efficiency. The entire chip was packaged to fit a com. multielectrode recording and stimulation system. Elec. recordings of spontaneous spikes from whole-mount neonatal mouse retinas were consistently obtained minutes after retinas were placed over the electrodes, exhibiting typical bursting and propagating waves. Most importantly, the signals obtained with carbon nanotube electrodes have exceptionally high signal to noise ratio, reaching values as high as 75. Moreover, spikes are marked by a conspicuous gradual increase in amplitude recorded over a period of minutes to hours, suggesting improvement in cell-electrode coupling. This phenomenon is not obsd. in conventional com. electrodes. Elec. stimulation using carbon nanotube electrodes was also achieved. We attribute the superior performances of the carbon nanotube electrodes to their three dimensional nature and the strong neuro-carbon nanotube affinity. The results presented here show the great potential of carbon nanotube electrodes for retinal interfacing applications. Specifically, our results demonstrate a route to achieve a redn. of the electrode down to few micrometers in order to achieve high efficacy local stimulation needed in retinal prosthetic devices.
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116Wong, W. T.; Sanes, J. R.; Wong, R. O. L. Developmentally Regulated Spontaneous Activity in the Embryonic Chick Retina. J. Neurosci. 1998, 18 (21), 8839– 8852, DOI: 10.1523/JNEUROSCI.18-21-08839.1998116https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1cXntFOlu7w%253D&md5=36f824e5b14d985343c21dd82e869c54Developmentally regulated spontaneous activity in the embryonic chick retinaWong, Wai T.; Sanes, Joshua R.; Wong, Rachel O. L.Journal of Neuroscience (1998), 18 (21), 8839-8852CODEN: JNRSDS; ISSN:0270-6474. (Society for Neuroscience)Even before birth and the onset of sensory experience, neural activity plays an important role in shaping the vertebrate nervous system. In the embryonic chick visual system, activity in the retina before vision has been implicated in the refinement of retinotopic maps, the elimination of transient projections, and the survival of a full complement of neurons. In this study, the authors report the detection of a physiol. substrate for these phenomena: waves of spontaneous activity in the ganglion cell layer of the embryonic chick retina. The activity is robust and highly patterned, taking the form of large amplitude, rhythmic, and wide-ranging waves of excitation that propagate across the retina. Activity waves are most prominent and organized between embryonic days 13-18, coinciding with the developmental period during which retinal axons refine their connections in their targets. The spatial and temporal features of the patterns obsd. are consistent with the role of activity patterns in shaping eye-specific projections and retinotopic maps but inconsistent with the hypothesis that they specify lamina-specific projections in the tectum. Antagonists of glutamatergic and glycinergic transmission and of gap junctional communication suppress spontaneous activity, whereas antagonists to GABAergic transmission potentiate it. Based on these results, the authors propose that spontaneous activity in the ganglion cells is regulated by chem. inputs from both bipolar and amacrine cells and by gap junctional coupling involving ganglion cells.
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117Delori, F. C.; Webb, R. H.; Sliney, D. H. Maximum Permissible Exposures for Ocular Safety (ANSI 2000), with Emphasis on Ophthalmic Devices. J. Opt. Soc. Am. A 2007, 24 (5), 1250, DOI: 10.1364/JOSAA.24.001250117https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BD2s3itVGgsg%253D%253D&md5=399ddf15e62e762ac178ce6c2bea4b73Maximum permissible exposures for ocular safety (ANSI 2000), with emphasis on ophthalmic devicesDelori Francois C; Webb Robert H; Sliney David HJournal of the Optical Society of America. A, Optics, image science, and vision (2007), 24 (5), 1250-65 ISSN:1084-7529.After discussing the rationale and assumptions of the ANSI Z136.1-2000 Standard for protection of the human eye from laser exposure, we present the concise formulation of the exposure limits expressed as maximum permissible radiant exposure (in J/cm(2)) for light overfilling the pupil. We then translate the Standard to a form that is more practical for typical ophthalmic devices or in vision research situations, implementing the special qualifications of the Standard. The safety limits are then expressed as radiant power (watts) entering the pupil of the eye. Exposure by repetitive pulses is also addressed, as this is frequently employed in ophthalmic applications. Examples are given that will familiarize potential users with this format.
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118Yan, B.; Vakulenko, M.; Min, S. H.; Hauswirth, W. W.; Nirenberg, S. Maintaining Ocular Safety with Light Exposure, Focusing on Devices for Optogenetic Stimulation. Vision Res. 2016, 121, 57– 71, DOI: 10.1016/j.visres.2016.01.006118https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28jhtlSjsg%253D%253D&md5=17713785b62a0a0cd287d4a82aad4bfaMaintaining ocular safety with light exposure, focusing on devices for optogenetic stimulationYan Boyuan; Vakulenko Maksim; Min Seok-Hong; Hauswirth William W; Nirenberg SheilaVision research (2016), 121 (), 57-71 ISSN:.Optogenetics methods are rapidly being developed as therapeutic tools for treating neurological diseases, in particular, retinal degenerative diseases. A critical component of the development is testing the safety of the light stimulation used to activate the optogenetic proteins. While the stimulation needs to be sufficient to produce neural responses in the targeted retinal cell class, it also needs to be below photochemical and photothermal limits known to cause ocular damage. The maximal permissible exposure is determined by a variety of factors, including wavelength, exposure duration, visual angle, pupil size, pulse width, pulse pattern, and repetition frequency. In this paper, we develop utilities to systematically and efficiently assess the contributions of these parameters in relation to the limits, following directly from the 2014 American National Standards Institute (ANSI). We also provide an array of stimulus protocols that fall within the bounds of both safety and effectiveness. Additional verification of safety is provided with a case study in rats using one of these protocols.
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119Tamang, S.; Lincheneau, C.; Hermans, Y.; Jeong, S.; Reiss, P. Chemistry of InP Nanocrystal Syntheses. Chem. Mater. 2016, 28 (8), 2491– 2506, DOI: 10.1021/acs.chemmater.5b05044119https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XltFGnt7g%253D&md5=66b19e4be3d991d6612163e82596497aChemistry of InP Nanocrystal SynthesesTamang, Sudarsan; Lincheneau, Christophe; Hermans, Yannick; Jeong, Sohee; Reiss, PeterChemistry of Materials (2016), 28 (8), 2491-2506CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)A review. Chem. synthesized InP nanocrystals (NCs) are drawing a large interest as a potentially less toxic alternative to CdSe-based nanocrystals. With a bulk band gap of 1.35 eV and an exciton Bohr radius of ∼10 nm the emission wavelength of InP NCs can in principle be tuned throughout the whole visible and near-IR range by changing their size. A few works reported fluorescence quantum yields exceeding 70% after overcoating the core NCs with appropriate shell materials. Therefore, InP NCs are very promising for use in lighting and display applications. However, a no. of challenges remain to be addressed to progress from isolated research results to robust and reproducible synthesis methods for high quality InP NCs. First of all, the size distribution of the as-synthesized NCs needs to be reduced, which directly translates into more narrow emission line widths. Next, reliable protocols are required for achieving a given emission wavelength at high reaction yield and for further improving the emission efficiency and chem. and photostability. Advances in these directions were hampered for a long time by the specific properties of InP, such as the rather covalent nature of binding implying harsh synthesis conditions, high sensitivity toward oxidn., and limited choice of P precursors. However, in recent years a much better understanding of the precursor conversion kinetics and reaction mechanisms was achieved, giving this field new impulse. A comprehensive overview from initial synthetic approaches to the most recent developments is provided. First, the authors highlight the fundamental differences in the syntheses of InP-based NCs with respect to established II-VI and IV-VI semiconductor NCs comparing their nucleation and growth stages. Next, the authors inspect in detail the influence of the nature of the P and In precursors used and of reaction additives, such as Zn carboxylates or alkylamines, on the properties of the NCs. Finally, core/shell systems and doped InP NCs are discussed, and perspectives in this field are given.
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120Sargent, E. H. Colloidal Quantum Dot Solar Cells. Nat. Photonics 2012, 6 (3), 133– 135, DOI: 10.1038/nphoton.2012.33120https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XivV2ns7g%253D&md5=0e8f4729ee05fab745965fa0e1271059Colloidal quantum dot solar cellsSargent, Edward H.Nature Photonics (2012), 6 (3), 133-135CODEN: NPAHBY; ISSN:1749-4885. (Nature Publishing Group)A review. Solar cells based on soln.-processed semiconductor nanoparticles - colloidal quantum dots - have seen rapid advances in recent years. By offering full-spectrum solar harvesting, these cells are poised to address the urgent need for low-cost, high-efficiency photovoltaics.
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121Li, W.; Zhong, X. Capping Ligand-Induced Self-Assembly for Quantum Dot Sensitized Solar Cells. J. Phys. Chem. Lett. 2015, 6 (5), 796– 806, DOI: 10.1021/acs.jpclett.5b00001121https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXisF2isbY%253D&md5=d40c0968362f3f3f9a05c4b88b260728Capping Ligand-Induced Self-Assembly for Quantum Dot Sensitized Solar CellsLi, Wenjie; Zhong, XinhuaJournal of Physical Chemistry Letters (2015), 6 (5), 796-806CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)A review. Quantum dot-sensitized solar cells (QDSCs), having the advantages of low-cost assembling process, economically viable materials and intrinsic optoelectronic properties of QD sensitizers, are regarded as attractive candidates for the third-generation solar cells. In spite of the previous unsatisfied performance resulted from poor sensitization, an increasing power conversion efficiency has been exptl. confirmed with the development of effective deposition approaches in the last five years. In this perspective article, an overview is presented on versatile QD deposition methods, regarding mainly the effective loading of QDs and surface chem. issues. Linker-assisted assembly, a most efficient sensitizer deposition approach to achieve fast, uniform and dense coverage of the sensitizers on mesoporous TiO2 film electrode, is discussed with emphasis. Recent advances based on this deposition technique in achieving high efficiency are presented. Also, combined efforts regarding the overall improvement of the device have been discussed to provide more possible access to higher power conversion efficiencies of the QDSCs.
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122Yang, S.; Zhao, P.; Zhao, X.; Qu, L.; Lai, X. InP and Sn:InP Based Quantum Dot Sensitized Solar Cells. J. Mater. Chem. A 2015, 3 (43), 21922– 21929, DOI: 10.1039/C5TA04925C122https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsFWhtLzN&md5=175f194318bd7e347e6b8d9f76fe1ef9InP and Sn:InP based quantum dot sensitized solar cellsYang, Suolong; Zhao, Pengxiang; Zhao, Xiaochong; Qu, Liangti; Lai, XinchunJournal of Materials Chemistry A: Materials for Energy and Sustainability (2015), 3 (43), 21922-21929CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)Due to the ideal band gap and environmental friendliness, InP is a promising light-harvesting material in photovoltaic cells. However, green InP based quantum dot sensitized solar cells (QDSSCs) have been rarely reported. Herein, nearly monodispersed Sn doped InP (Sn:InP) quantum dots (QDs) were synthesized by the 1-pot nucleation doping method, and used as the sensitizer in the construction of QDSSCs. High QD loadings on the TiO2 film electrodes were achieved by using the capping ligand-induced self-assembly (CLIS) sensitization technique. The resulting champion Sn:InP cell shows a power conversion efficiency (PCE) of 3.54% under AM 1.5 G (simulated 1 sun illumination), which is remarkably higher than that of un-doped InP QD based ones. This improvement is ascribed to the regulation role of the band gap by Sn dopant in the InP QDs. The Sn:InP QDSSCs exhibit moderate efficiency, good reproducibility and stability. These new findings may pave the way for the performance improvements of other QD photovoltaic devices.
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123Yang, Z.; Chen, C. Y.; Roy, P.; Chang, H. T. Quantum Dot-Sensitized Solar Cells Incorporating Nanomaterials. Chem. Commun. 2011, 47 (34), 9561– 9571, DOI: 10.1039/c1cc11317h123https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtVWgs7zF&md5=3580778444a1677fe892d14b6af25aa7Quantum dot-sensitized solar cells incorporating nanomaterialsYang, Zusing; Chen, Chia-Ying; Roy, Prathik; Chang, Huan-TsungChemical Communications (Cambridge, United Kingdom) (2011), 47 (34), 9561-9571CODEN: CHCOFS; ISSN:1359-7345. (Royal Society of Chemistry)Quantum dot-sensitized solar cells (QDSSCs) are interesting energy devices because of their (i) impressive ability to harvest sunlight and generate multiple electron/hole pairs, (ii) ease of fabrication, and (iii) low cost. The power conversion efficiencies (η) of most QDSSCs (typically < 4%) are, however, less than those (up to 12%) of dye-sensitized solar cells, mainly because of narrow absorption ranges and charge recombination occurring at the QD-electrolyte and TiO2-electrolyte interfaces. To further increase the values of η of QDSSCs, it will be necessary to develop new types of working electrodes, sensitizers, counter electrodes, and electrolytes. This article describes the nanomaterials that were used recently as electronic conductors, sensitizers, and counter electrodes in QDSSCs. The nature, size, morphol., and quantity of these nanomaterials all play important roles affecting the efficiencies of electron injection and light harvesting. The behavior is discussed of several important types of semiconductor nanomaterials (sensitizers, including CdS, Ag2S, CdSe, CdTe, CdHgTe, InAs, and PbS) and nanomaterials (notably TiO2, ZnO, and carbon-based species) that were developed to improve the electron transport efficiency of QDSSCs. The prepn. is pointed out of new generations of nanomaterials for QDSSCs and the types of electrolytes, particularly iodide/triiodide electrolytes (I-/I3-), polysulfide electrolytes (S2-/Sx2-), and cobalt redox couples ([Co(o-phen)32+/3+]), that improve their lifetimes. With advances in nanotechnol., significant improvements are foreseen in the efficiency (η > 6%) and durability (> 3000 h) of QDSSCs.
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124Medintz, I. L.; Uyeda, H. T.; Goldman, E. R.; Mattoussi, H. Quantum Dot Bioconjugates for Imaging, Labelling and Sensing. Nat. Mater. 2005, 4 (6), 435– 446, DOI: 10.1038/nmat1390124https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXks1Cit7k%253D&md5=5a012c5b15547485aeea42f41d212b45Quantum dot bioconjugates for imaging, labelling and sensingMedintz, Igor L.; Uyeda, H. Tetsuo; Goldman, Ellen R.; Mattoussi, HediNature Materials (2005), 4 (6), 435-446CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)A review. One of the fastest moving and most exciting interfaces of nanotechnol. is the use of quantum dots (QDs) in biol. The unique optical properties of QDs make them appealing as in vivo and in vitro fluorophores in a variety of biol. investigations, in which traditional fluorescent labels based on org. mols. fall short of providing long-term stability and simultaneous detection of multiple signals. The ability to make QDs water sol. and target them to specific biomols. has led to promising applications in cellular labeling, deep-tissue imaging, assay labeling and as efficient fluorescence resonance energy transfer donors. Despite recent progress, much work still needs to be done to achieve reproducible and robust surface functionalization and develop flexible bioconjugation techniques. In this review, we look at current methods for prepg. QD bioconjugates as well as presenting an overview of applications. The potential of QDs in biol. has just begun to be realized and new avenues will arise as our ability to manipulate these materials improves.
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125Livache, C.; Martinez, B.; Goubet, N.; Gréboval, C.; Qu, J.; Chu, A.; Royer, S.; Ithurria, S.; Silly, M. G.; Dubertret, B.; Lhuillier, E. A Colloidal Quantum Dot Infrared Photodetector and Its Use for Intraband Detection. Nat. Commun. 2019, 10 (1), 2125, DOI: 10.1038/s41467-019-10170-8125https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BB3M7kt1WrsA%253D%253D&md5=85ad17dbd68b7eb6d9d145f5e040eed5A colloidal quantum dot infrared photodetector and its use for intraband detectionLivache Clement; Martinez Bertille; Goubet Nicolas; Greboval Charlie; Qu Junling; Chu Audrey; Royer Sebastien; Lhuillier Emmanuel; Livache Clement; Martinez Bertille; Goubet Nicolas; Ithurria Sandrine; Dubertret Benoit; Silly Mathieu GNature communications (2019), 10 (1), 2125 ISSN:.Wavefunction engineering using intraband transition is the most versatile strategy for the design of infrared devices. To date, this strategy is nevertheless limited to epitaxially grown semiconductors, which lead to prohibitive costs for many applications. Meanwhile, colloidal nanocrystals have gained a high level of maturity from a material perspective and now achieve a broad spectral tunability. Here, we demonstrate that the energy landscape of quantum well and quantum dot infrared photodetectors can be mimicked from a mixture of mercury selenide and mercury telluride nanocrystals. This metamaterial combines intraband absorption with enhanced transport properties (i.e. low dark current, fast time response and large thermal activation energy). We also integrate this material into a photodiode with the highest infrared detection performances reported for an intraband-based nanocrystal device. This work demonstrates that the concept of wavefunction engineering at the device scale can now be applied for the design of complex colloidal nanocrystal-based devices.
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126Meinardi, F.; McDaniel, H.; Carulli, F.; Colombo, A.; Velizhanin, K. A.; Makarov, N. S.; Simonutti, R.; Klimov, V. I.; Brovelli, S. Highly Efficient Large-Area Colourless Luminescent Solar Concentrators Using Heavy-Metal-Free Colloidal Quantum Dots. Nat. Nanotechnol. 2015, 10 (10), 878– 885, DOI: 10.1038/nnano.2015.178126https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlyls7vO&md5=b63662c4e01349d552589031b5cc71deHighly efficient large-area colorless luminescent solar concentrators using heavy-metal-free colloidal quantum dotsMeinardi, Francesco; McDaniel, Hunter; Carulli, Francesco; Colombo, Annalisa; Velizhanin, Kirill A.; Makarov, Nikolay S.; Simonutti, Roberto; Klimov, Victor I.; Brovelli, SergioNature Nanotechnology (2015), 10 (10), 878-885CODEN: NNAABX; ISSN:1748-3387. (Nature Publishing Group)Luminescent solar concentrators serving as semitransparent photovoltaic windows could become an important element in net zero energy consumption buildings of the future. Colloidal quantum dots are promising materials for luminescent solar concentrators as they can be engineered to provide the large Stokes shift necessary for suppressing reabsorption losses in large-area devices. Existing Stokes-shift-engineered quantum dots allow for only partial coverage of the solar spectrum, which limits their light-harvesting ability and leads to coloring of the luminescent solar concentrators, complicating their use in architecture. Here, we use quantum dots of ternary I-III-VI2 semiconductors to realize the first large-area quantum dot-luminescent solar concentrators free of toxic elements, with reduced reabsorption and extended coverage of the solar spectrum. By incorporating CuInSexS2-x quantum dots into photo-polymd. poly(lauryl methacrylate), we obtain freestanding, colorless slabs that introduce no distortion to perceived colors and are thus well suited for the realization of photovoltaic windows. Thanks to the suppressed reabsorption and high emission efficiencies of the quantum dots, we achieve an optical power efficiency of 3.2%. Ultrafast spectroscopy studies suggest that the Stokes-shifted emission involves a conduction-band electron and a hole residing in an intragap state assocd. with a native defect.
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127Sadeghi, S.; Bahmani Jalali, H.; Srivastava, S. B.; Melikov, R.; Baylam, I.; Sennaroglu, A.; Nizamoglu, S. High-Performance, Large-Area, and Ecofriendly Luminescent Solar Concentrators Using Copper-Doped InP Quantum Dots. iScience 2020, 23 (7), 101272, DOI: 10.1016/j.isci.2020.101272127https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtlWqtLrK&md5=7b50f8236f47e3addfe2e07750909c95High-Performance, Large-Area, and Ecofriendly Luminescent Solar Concentrators Using Copper-Doped InP Quantum DotsSadeghi, Sadra; Bahmani Jalali, Houman; Srivastava, Shashi Bhushan; Melikov, Rustamzhon; Baylam, Isinsu; Sennaroglu, Alphan; Nizamoglu, SedatiScience (2020), 23 (7), 101272CODEN: ISCICE; ISSN:2589-0042. (Elsevier B.V.)Colloidal quantum dots (QDs) are promising building blocks for luminescent solar concentrators (LSCs). For their widespread use, they need to simultaneously satisfy non-toxic material content, low reabsorption, high photoluminescence quantum yield, and large-scale prodn. Here, copper doping of zinc carboxylate-passivated InP core and nano-engineering of ZnSe shell facilitated high in-device quantum efficiency of QDs over 80%, having well-matched spectral emission profile with the photo-response of silicon solar cells. The optimized QD-LSCs showed an optical quantum efficiency of 37% and an internal concn. factor of 4.7 for a 10 x 10-cm2 device area under solar illumination, which is comparable with the state-of-the-art LSCs based on cadmium-contg. QDs and lead-contg. perovskites. Synthesis of the copper-doped InP/ZnSe QDs in gram-scale and large-area deposition (3,000 cm2) onto com. window glasses via doctor-blade technique showed their scalability for mass prodn. These results position InP-based QDs as a promising alternative for efficient solar energy harvesting.
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128Sadeghi, S.; Bahmani Jalali, H.; Melikov, R.; Ganesh Kumar, B.; Mohammadi Aria, M.; Ow-Yang, C. W.; Nizamoglu, S. Stokes-Shift-Engineered Indium Phosphide Quantum Dots for Efficient Luminescent Solar Concentrators. ACS Appl. Mater. Interfaces 2018, 10 (15), 12975– 12982, DOI: 10.1021/acsami.7b19144128https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXmt1Wksr0%253D&md5=df0a7a1b4b4f73e4b3a29e330ca7ba1eStokes-Shift-Engineered Indium Phosphide Quantum Dots for Efficient Luminescent Solar ConcentratorsSadeghi, Sadra; Bahmani Jalali, Houman; Melikov, Rustamzhon; Ganesh Kumar, Baskaran; Mohammadi Aria, Mohammad; Ow-Yang, Cleva W.; Nizamoglu, SedatACS Applied Materials & Interfaces (2018), 10 (15), 12975-12982CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Luminescent solar concentrators (LSCs) show promise because of their potential for low-cost, large-area, and high-efficiency energy harvesting. Stokes shift engineering of luminescent quantum dots (QDs) is a favorable approach to suppress reabsorption losses in LSCs; however, the use of highly toxic heavy metals in QDs constitutes a serious concern for environmental sustainability. Here, we report LSCs based on cadmium-free InP/ZnO core/shell QDs with type-II band alignment that allow for the suppression of reabsorption by Stokes shift engineering. The spectral emission and absorption overlap was controlled by the growth of a ZnO shell on an InP core. At the same time, the ZnO layer also facilitates the photostability of the QDs within the host matrix. We analyzed the optical performance of indium-based LSCs and identified the optical efficiency as 1.45%. The transparency, flexibility, and cadmium-free content of the LSCs hold promise for solar window applications.
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129Bahmani Jalali, H.; Sadeghi, S.; Baylam, I.; Han, M.; Ow-Yang, C. W.; Sennaroglu, A.; Nizamoglu, S. Exciton Recycling via InP Quantum Dot Funnels for Luminescent Solar Concentrators. Nano Res. 2021, 14 (5), 1488– 1494, DOI: 10.1007/s12274-020-3207-9129https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhtVKntr7J&md5=fd289da0f19bcf3879fb8e8eb9a7d87aExciton recycling via InP quantum dot funnels for luminescent solar concentratorsBahmani Jalali, Houman; Sadeghi, Sadra; Baylam, Isinsu; Han, Mertcan; Ow-Yang, Cleva W.; Sennaroglu, Alphan; Nizamoglu, SedatNano Research (2021), 14 (5), 1488-1494CODEN: NRAEB5; ISSN:1998-0000. (Springer GmbH)Luminescent solar concentrators (LSC) absorb large-area solar radiation and guide down-converted emission to solar cells for electricity prodn. Quantum dots (QDs) have been widely engineered at device and quantum dot levels for LSCs. Here, we demonstrate cascaded energy transfer and exciton recycling at nanoassembly level for LSCs. The graded structure composed of different sized toxic-heavy-metal-free InP/ZnS core/shell QDs incorporated on copper doped InP QDs, facilitating exciton routing toward narrow band gap QDs at a high nonradiative energy transfer efficiency of 66%. At the final stage of non-radiative energy transfer, the photogenerated holes make ultrafast electronic transitions to copper-induced mid-gap states for radiative recombination in the near-IR. The exciton recycling facilitates a photoluminescence quantum yield increase of 34% and 61% in comparison with semi-graded and ungraded energy profiles, resp. Thanks to the suppressed reabsorption and enhanced photoluminescence quantum yield, the graded LSC achieved an optical quantum efficiency of 22.2%. Hence, engineering at nanoassembly level combined with nonradiative energy transfer and exciton funneling offer promise for efficient solar energy harvesting. [graphic not available: see fulltext].
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130Jang, E.; Kim, Y.; Won, Y.-H.; Jang, H.; Choi, S.-M. Environmentally Friendly InP-Based Quantum Dots for Efficient Wide Color Gamut Displays. ACS Energy Lett. 2020, 5 (4), 1316– 1327, DOI: 10.1021/acsenergylett.9b02851130https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXlt1Sjtb8%253D&md5=5793bd9310fbf4b814126b44ce6207a3Environmentally friendly InP-vased quantum dots for efficient wide color gamut displaysJang, Eunjoo; Kim, Yongwook; Won, Yu-Ho; Jang, Hyosook; Choi, Seon-MyeongACS Energy Letters (2020), 5 (4), 1316-1327CODEN: AELCCP; ISSN:2380-8195. (American Chemical Society)A review. Quantum dots (QD) are regarded as ideal light emitters for current and next-generation displays. Hence, there is an urgent need to produce environmentally friendly QDs that show high efficiency and better color purity. From this perspective, a strategy of tuning the wavelength and spectral width is discussed to optimize the brightness and color space agreement. The crit. parameters affecting photophys. properties, such as the uniformity of the InP QD core, the thickness and shape of the ZnSe shell, the electron/hole distribution, surface dangling defects, oxidative phase, and the stacking faults in the cryst. structure, are examd. In addn., quant. analyses are suggested to understand the nature of the ligands so that practical applications can be diversified. Recently, QD-LEDs using InP-based QDs with controlled shell structure showed potential for future commercialization. For further development, improvement in the stability via the control of inorg. and org. passivating structures is required.
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131Eren, G. O.; Sadeghi, S.; Bahmani Jalali, H.; Ritter, M.; Han, M.; Baylam, I.; Melikov, R.; Onal, A.; Oz, F.; Sahin, M.; Ow-Yang, C. W.; Sennaroglu, A.; Lechner, R. T.; Nizamoglu, S. Cadmium-Free and Efficient Type-II InP/ZnO/ZnS Quantum Dots and Their Application for LEDs. ACS Appl. Mater. Interfaces 2021, 13 (27), 32022– 32030, DOI: 10.1021/acsami.1c08118131https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXhsVelt7jP&md5=fcdf82cc7f9bcfad6ceae00822697b26Cadmium-Free and Efficient Type-II InP/ZnO/ZnS Quantum Dots and Their Application for LEDsEren, Guncem Ozgun; Sadeghi, Sadra; Bahmani Jalali, Houman; Ritter, Maximilian; Han, Mertcan; Baylam, Isinsu; Melikov, Rustamzhon; Onal, Asim; Oz, Fatma; Sahin, Mehmet; Ow-Yang, Cleva W.; Sennaroglu, Alphan; Lechner, Rainer T.; Nizamoglu, SedatACS Applied Materials & Interfaces (2021), 13 (27), 32022-32030CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)It is a generally accepted perspective that type-II nanocrystal quantum dots (QDs) have low quantum yield due to the sepn. of the electron and hole wavefunctions. Recently, high quantum yield levels were reported for cadmium-based type-II QDs. Hence, the quest for finding non-toxic and efficient type-II QDs is continuing. Herein, we demonstrate environmentally benign type-II InP/ZnO/ZnS core/shell/shell QDs that reach a high quantum yield of ~ 91%. For this, ZnO layer was grown on core InP QDs by thermal decompn., which was followed by a ZnS layer via successive ionic layer adsorption. The small-angle X-ray scattering shows that spherical InP core and InP/ZnO core/shell QDs turn into elliptical particles with the growth of the ZnS shell. To conserve the quantum efficiency of QDs in device architectures, InP/ZnO/ZnS QDs were integrated in the liq. state on blue light-emitting diodes (LEDs) as down-converters that led to an external quantum efficiency of 9.4% and a power conversion efficiency of 6.8%, resp., which is the most efficient QD-LED using type-II QDs. This study pointed out that cadmium-free type-II QDs can reach high efficiency levels, which can stimulate novel forms of devices and nanomaterials for bioimaging, display, and lighting.
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132Yong, K. T.; Ding, H.; Roy, I.; Law, W. C.; Bergey, E. J.; Maitra, A.; Prasad, P. N. Imaging Pancreatic Cancer Using Bioconjugated Inp Quantum Dots. ACS Nano 2009, 3 (3), 502– 510, DOI: 10.1021/nn8008933132https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXitlyrsbs%253D&md5=5695dde181f28ace6c4085a42d51a5f9Imaging Pancreatic Cancer Using Bioconjugated InP Quantum DotsYong, Ken-Tye; Ding, Hong; Roy, Indrajit; Law, Wing-Cheung; Bergey, Earl J.; Maitra, Anirban; Prasad, Paras N.ACS Nano (2009), 3 (3), 502-510CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)In this paper, the authors report the successful use of non-cadmium-based quantum dots (QDs) as highly efficient and nontoxic optical probes for imaging live pancreatic cancer cells. Indium phosphide (core)-zinc sulfide (shell), or InP/ZnS, QDs with high quality and bright luminescence were prepd. by a hot colloidal synthesis method in nonaq. media. The surfaces of these QDs were then functionalized with mercaptosuccinic acid to make them highly dispersible in aq. media. Further bioconjugation with pancreatic cancer specific monoclonal antibodies, such as anticlaudin 4 and antiprostate stem cell antigen (anti-PSCA), to the functionalized InP/ZnS QDs, allowed specific in vitro targeting of pancreatic cancer cell lines (both immortalized and low passage ones). The receptor-mediated delivery of the bioconjugates was further confirmed by the observation of poor in vitro targeting in nonpancreatic cancer based cell lines which are neg. for the claudin-4-receptor. These observations suggest the immense potential of InP/ZnS QDs as non-cadmium-based safe and efficient optical imaging nanoprobes in diagnostic imaging, particularly for early detection of cancer.
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133Lin, G.; Ouyang, Q.; Hu, R.; Ding, Z.; Tian, J.; Yin, F.; Xu, G.; Chen, Q.; Wang, X.; Yong, K. T. In Vivo Toxicity Assessment of Non-Cadmium Quantum Dots in BALB/c Mice. Nanomedicine Nanotechnology, Biol. Med. 2015, 11 (2), 341– 350, DOI: 10.1016/j.nano.2014.10.002133https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2MzjsVCisA%253D%253D&md5=689dea0989f9b6334082c4c58c1654e2In vivo toxicity assessment of non-cadmium quantum dots in BALB/c miceLin Guimiao; Ding Zhangchi; Tian Jinglin; Chen Qiang; Wang Xiaomei; Ouyang Qingling; Hu Rui; Yin Feng; Xu Gaixia; Yong Ken-TyeNanomedicine : nanotechnology, biology, and medicine (2015), 11 (2), 341-50 ISSN:.Along with widespread usage of QDs in electronic and biomedical industries, the likelihood of QDs exposure to the environment and humans is deemed to occur when the QD products are degraded or handled as waste for processing. To date, there are very few toxicological reports available in the literature for non-cadmium QDs in animal models. In this work, we studied the long term in vivo toxicity of InP/ZnS QDs in BALB/c mice. The biodistribution, body weight, hematology, blood biochemistry, and organ histology were determined at a very high dosage (25 mg/kg) of InP/ZnS QDs over 84 days period. Our results manifested that the QDs formulation did not result in observable toxicity in vivo within the evaluation period, thereby suggesting that the InP/ZnS QDs can be utilized as optical probes or nanocarrier for selected in vivo biological applications when an optimized dosage is employed. FROM THE CLINICAL EDITOR: This study investigated the toxicity of quantum dots in BALB/c mice, and concluded that no organotoxicity was detectable despite of using high concentration of InP/ZnS quantum dots with prolonged exposure of 3 months.
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134Van De Walle, C. G. Universal Alignment of Hydrogen Levels in Semiconductors and Insulators. Phys. B Condens. Matter 2006, 376–377 (1), 1– 6, DOI: 10.1016/j.physb.2005.12.004134https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XivVGntb0%253D&md5=e06f62d413308d0bc80abfa71fff3babUniversal alignment of hydrogen levels in semiconductors and insulatorsVan de Walle, Chris G.Physica B: Condensed Matter (Amsterdam, Netherlands) (2006), 376-377 (), 1-6CODEN: PHYBE3; ISSN:0921-4526. (Elsevier B.V.)H strongly affects the properties of electronic materials. It is always elec. active, and usually counteracts the prevailing cond. of the semiconductor. In some materials, however, H acts as a source of doping. We have developed a model that enables us to predict the elec. activity of H in any material, based on its band alignment on an abs. energy scale. We discuss the underlying physics, as well as consequences for specific materials, including ZnO and GaN.
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135Shankara Narayanan, S.; Sinha, S. S.; Verma, P. K.; Pal, S. K. Ultrafast Energy Transfer from 3-Mercaptopropionic Acid-Capped CdSe/ZnS QDs to Dye-Labelled DNA. Chem. Phys. Lett. 2008, 463 (1–3), 160– 165, DOI: 10.1016/j.cplett.2008.08.057There is no corresponding record for this reference.
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136Sada, N.; Lee, S.; Katsu, T.; Otsuki, T.; Inoue, T. Targeting LDH Enzymes with a Stiripentol Analog to Treat Epilepsy. Science (80-.). 2015, 347 (6228), 1362– 1367, DOI: 10.1126/science.aaa1299There is no corresponding record for this reference.
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137Han, X.; Boyden, E. S. Multilpe-Color Optical Activation, Silencing, and Desynchronization of Neural Activity, with Single-Spike Temporal Resolution. PLoS One 2007, 2 (3), e299 DOI: 10.1371/journal.pone.0000299There is no corresponding record for this reference.
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138Han, M.; Srivastava, S. B.; Yildiz, E.; Melikov, R.; Surme, S.; Dogru-Yuksel, I. B.; Kavakli, I. H.; Sahin, A.; Nizamoglu, S. Organic Photovoltaic Pseudocapacitors for Neurostimulation. ACS Appl. Mater. Interfaces 2020, 12 (38), 42997– 43008, DOI: 10.1021/acsami.0c11581138https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhs12rtrzF&md5=1a37a254c83b8159bae70b6f77168a78Organic Photovoltaic Pseudocapacitors for NeurostimulationHan, Mertcan; Srivastava, Shashi Bhushan; Yildiz, Erdost; Melikov, Rustamzhon; Surme, Saliha; Dogru-Yuksel, Itir Bakis; Kavakli, Ibrahim Halil; Sahin, Afsun; Nizamoglu, SedatACS Applied Materials & Interfaces (2020), 12 (38), 42997-43008CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Neural interfaces are the fundamental tools to understand the brain and cure many nervous-system diseases. For proper interfacing, seamless integration, efficient and safe digital-to-biol. signal transduction, and long operational lifetime are required. Here, we devised a wireless optoelectronic pseudocapacitor converting the optical energy to safe capacitive currents by dissocg. the photogenerated excitons in the photovoltaic unit and effectively routing the holes to the supercapacitor electrode and the pseudocapacitive electrode-electrolyte interfacial layer of PEDOT:PSS for reversible faradic reactions. The biointerface showed high peak capacitive currents of ~ 3 mA·cm-2 with total charge injection of ~ 1μC·cm-2 at responsivity of 30 mA·W-1, generating high photovoltages over 400 mV for the main eye photoreception colors of blue, green, and red. Moreover, modification of PEDOT:PSS controls the charging/discharging phases leading to rapid capacitive photoresponse of 50μs and effective membrane depolarization at the single-cell level. The neural interface has a device lifetime of over 1.5 years in the aq. environment and showed stability without significant performance decrease after sterilization steps. Our results demonstrate that adopting the pseudocapacitance phenomenon on org. photovoltaics paves an ultraefficient, safe, and robust way toward communicating with biol. systems.
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139Yang, Y.; Zhang, Z. G.; Bin, H.; Chen, S.; Gao, L.; Xue, L.; Yang, C.; Li, Y. Side-Chain Isomerization on an n-Type Organic Semiconductor ITIC Acceptor Makes 11.77% High Efficiency Polymer Solar Cells. J. Am. Chem. Soc. 2016, 138 (45), 15011– 15018, DOI: 10.1021/jacs.6b09110139https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhslCgsLrP&md5=54040cde48b96af634ca492f9bf79198Side-Chain Isomerization on an n-type Organic Semiconductor ITIC Acceptor Makes 11.77% High Efficiency Polymer Solar CellsYang, Yankang; Zhang, Zhi-Guo; Bin, Haijun; Chen, Shanshan; Gao, Liang; Xue, Lingwei; Yang, Changduk; Li, YongfangJournal of the American Chemical Society (2016), 138 (45), 15011-15018CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Low bandgap n-type org. semiconductor (n-OS) ITIC has attracted great attention for the application as an acceptor with medium bandgap p-type conjugated polymer as donor in nonfullerene polymer solar cells (PSCs) because of its attractive photovoltaic performance. Here the authors report a modification on the mol. structure of ITIC by side-chain isomerization with meta-alkyl-Ph substitution, m-ITIC, to further improve its photovoltaic performance. In a comparison with its isomeric counterpart ITIC with para-alkyl-Ph substitution, m-ITIC shows a higher film absorption coeff., a larger cryst. coherence, and higher electron mobility. These inherent advantages of m-ITIC resulted in a higher power conversion efficiency (PCE) of 11.77% for the nonfullerene PSCs with m-ITIC as acceptor and a medium bandgap polymer J61 as donor, which is significantly improved over that (10.57%) of the corresponding devices with ITIC as acceptor. The PCE of 11.77% is one of the highest values reported in the literature to date for nonfullerene PSCs. More importantly, the m-ITIC-based device shows less thickness-dependent photovoltaic behavior than ITIC-based devices in the active-layer thickness range of 80-360 nm, which is beneficial for large area device fabrication. M-ITIC is a promising low bandgap n-OS for the application as an acceptor in PSCs, and the side-chain isomerization could be an easy and convenient way to further improve the photovoltaic performance of the donor and acceptor materials for high efficiency PSCs.
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140Kramer, I. J.; Sargent, E. H. The Architecture of Colloidal Quantum Dot Solar Cells: Materials to Devices. Chem. Rev. 2014, 114 (1), 863– 882, DOI: 10.1021/cr400299t140https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhsVygu7bN&md5=ccf7ecc0222c6ee778776ec0921db5c5The Architecture of Colloidal Quantum Dot Solar Cells: Materials to DevicesKramer, Illan J.; Sargent, Edward H.Chemical Reviews (Washington, DC, United States) (2014), 114 (1), 863-882CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review; architecture of colloidal quantum dot solar cells materials to devices is discussed.
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141Johnston, K. W.; Pattantyus-Abraham, A. G.; Clifford, J. P.; Myrskog, S. H.; Hoogland, S.; Shukla, H.; Klem, E. J. D.; Levina, L.; Sargent, E. H. Efficient Schottky-Quantum-Dot Photovoltaics: The Roles of Depletion, Drift, and Diffusion. Appl. Phys. Lett. 2008, 92 (12), 122111, DOI: 10.1063/1.2896295141https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXksF2rs7w%253D&md5=1f29db298d229c16a68a16ccc12a5906Efficient Schottky-quantum-dot photovoltaics. The roles of depletion, drift, and diffusionJohnston, Keith W.; Pattantyus-Abraham, Andras G.; Clifford, Jason P.; Myrskog, Stefan H.; Hoogland, Sjoerd; Shukla, Harnik; Klem, Ethan J. D.; Levina, Larissa; Sargent, Edward H.Applied Physics Letters (2008), 92 (12), 122111/1-122111/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)PbS colloidal quantum dot photovoltaic devices in a Schottky architecture have demonstrated an IR power conversion efficiency of 4.2%. Here, we elucidate the internal mechanisms leading to this efficiency. At relevant intensities, the drift length is 10 μm for holes and 1 μm for electrons. Transport within the 150 nm wide depletion region is therefore highly efficient. The electron diffusion length of 0.1 μm is comparable to neutral region width. We quant. account for the obsd. 37% external quantum efficiency, showing that it results from the large depletion width and long carrier lifetime combined. (c) 2008 American Institute of Physics.
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142Parameswaran, R.; Carvalho-De-Souza, J. L.; Jiang, Y.; Burke, M. J.; Zimmerman, J. F.; Koehler, K.; Phillips, A. W.; Yi, J.; Adams, E. J.; Bezanilla, F.; Tian, B. Photoelectrochemical Modulation of Neuronal Activity with Free-Standing Coaxial Silicon Nanowires. Nat. Nanotechnol. 2018, 13 (3), 260– 266, DOI: 10.1038/s41565-017-0041-7142https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXjtFKqu7g%253D&md5=13d95a520bfecbbcefba44e4c5a27d80Photoelectrochemical modulation of neuronal activity with free-standing coaxial silicon nanowiresParameswaran, Ramya; Carvalho-de-Souza, Joao L.; Jiang, Yuanwen; Burke, Michael J.; Zimmerman, John F.; Koehler, Kelliann; Phillips, Andrew W.; Yi, Jaeseok; Adams, Erin J.; Bezanilla, Francisco; Tian, BozhiNature Nanotechnology (2018), 13 (3), 260-266CODEN: NNAABX; ISSN:1748-3387. (Nature Research)Optical methods for modulating cellular behavior are promising for both fundamental and clin. applications. However, most available methods are either mech. invasive, require genetic manipulation of target cells or cannot provide subcellular specificity. Here, we address all these issues by showing optical neuromodulation with free-standing coaxial p-type/intrinsic/n-type silicon nanowires. We reveal the presence of at. gold on the nanowire surfaces, likely due to gold diffusion during the material growth. To evaluate how surface gold impacts the photoelectrochem. properties of single nanowires, we used modified quartz pipettes from a patch clamp and recorded sustained cathodic photocurrents from single nanowires. We show that these currents can elicit action potentials in primary rat dorsal root ganglion neurons through a primarily at. gold-enhanced photoelectrochem. process.
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143Lv, H.; Wang, C.; Li, G.; Burke, R.; Krauss, T. D.; Gao, Y.; Eisenberg, R. Semiconductor Quantum Dot-Sensitized Rainbow Photocathode for Effective Photoelectrochemical Hydrogen Generation. Proc. Natl. Acad. Sci. U. S. A. 2017, 114 (43), 11297– 11302, DOI: 10.1073/pnas.1712325114143https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1aju7fL&md5=2871717e6e7517fa1ee6af1f3edee645Semiconductor quantum dot-sensitized rainbow photocathode for effective photoelectrochemical hydrogen generationLv, Hongjin; Wang, Congcong; Li, Guocan; Burke, Rebeckah; Krauss, Todd D.; Gao, Yongli; Eisenberg, RichardProceedings of the National Academy of Sciences of the United States of America (2017), 114 (43), 11297-11302CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)The present study reports the fabrication of CdSe quantum dot (QD)-sensitized photocathodes on NiO-coated In Sn oxide (ITO) electrodes and their H2-generating ability upon light irradn. A well-established spin-coating method was used to deposit CdSe QD stock soln. onto the surface of NiO/ITO electrodes, thereby leading to the construction of various CdSe QD-sensitized photocathodes. The present report includes the construction of rainbow photocathodes by spin-coating different-sized QDs in a sequentially layered manner, thereby creating an energetically favorable gradient for charge sepn. The resulting rainbow photocathodes with forward energetic gradient for charge sepn. and subsequent electron transfer to a soln.-based H-evolving catalyst (HEC) exhibit good light-harvesting ability and enhanced photo-responses compared with the reverse rainbow photocathodes under white LED light illumination. Under minimally optimized conditions, a photocurrent d. of ≤115 μA cm-2 and a faradaic efficiency of 99.5% are achieved, which is among the most effective QD-based photocathode H2O-splitting systems.
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144Mirkovic, T.; Ostroumov, E. E.; Anna, J. M.; Van Grondelle, R.; Govindjee; Scholes, G. D. Light Absorption and Energy Transfer in the Antenna Complexes of Photosynthetic Organisms. Chem. Rev. 2017, 117 (2), 249– 293, DOI: 10.1021/acs.chemrev.6b00002144https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFyit7vI&md5=7201884bb63ab70347f79f951ff3369aLight absorption and energy transfer in the antenna complexes of photosynthetic organismsMirkovic, Tihana; Ostroumov, Evgeny E.; Anna, Jessica M.; van Grondelle, Rienk; Govindjee; Scholes, Gregory D.Chemical Reviews (Washington, DC, United States) (2017), 117 (2), 249-293CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)A review. The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing mols. (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solns. for light harvesting. In this review, we describe the underlying photophys. principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET). First, optical properties of the individual pigment chromophores present in light-harvesting antenna complexes are introduced, and then we examine the collective behavior of pigment-pigment and pigment-protein interactions. The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment mols. In the latter half of the article, we focus on the light-harvesting complexes of purple bacteria as a model to illustrate the present understanding of the synergetic effects leading to EET optimization of light-harvesting antenna systems while exploring the structure and function of the integral chromophores. We end this review with a brief overview of the energy-transfer dynamics and pathways in the light-harvesting antennas of various photosynthetic organisms.
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145Bahmani Jalali, H.; Melikov, R.; Sadeghi, S.; Nizamoglu, S. Excitonic Energy Transfer within InP/ZnS Quantum Dot Langmuir-Blodgett Assemblies. J. Phys. Chem. C 2018, 122 (22), 11616– 11622, DOI: 10.1021/acs.jpcc.8b00744145https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXptVCjsbk%253D&md5=c3b61852bb2f2992698c6714e6cc4314Excitonic Energy Transfer within InP/ZnS Quantum Dot Langmuir-Blodgett AssembliesBahmani Jalali, Houman; Melikov, Rustamzhon; Sadeghi, Sadra; Nizamoglu, SedatJournal of Physical Chemistry C (2018), 122 (22), 11616-11622CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)InP/ZnS core/shell quantum dot monolayers were assembled via the Langmuir-Blodgett technique, and the effect of ZnS shell thickness on the excitonic energy transfer within these core/shell quantum dots was studied. Three types of InP-based core/shell quantum dot Langmuir-Blodgett assemblies with different ZnS shell thicknesses were assembled. The structural and optical properties of colloidal quantum dots reveal the successful multiple ZnS shell growth, and at. force microscopy studies show the smoothness of the assembled monolayers. Time-resolved luminescence (PL) and fluorescence lifetime imaging microscopy (FLIM) studies of the thick-shell QD monolayer reveal narrower lifetime distribution in comparison with the thin-shell QD monolayer. The interparticle excitonic energy transfer was studied by spectrally resolved PL traces, and higher energy transfer was obsd. for the thin-shell InP/1ZnS QD monolayer. Finally, the authors calcd. the av. exciton energy and indicated that the energy transfer induced exciton energy shift decreased significantly from 95 to 27 meV after multiple ZnS shell growth.
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146Kumar, B. G.; Sadeghi, S.; Melikov, R.; Aria, M. M.; Jalali, H. B.; Ow-Yang, C. W.; Nizamoglu, S. Structural Control of InP/ZnS Core/Shell Quantum Dots Enables High-Quality White LEDs. Nanotechnology 2018, 29 (34), 345605, DOI: 10.1088/1361-6528/aac8c9146https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXisVansLnF&md5=64d5b1b83ce61f5071eab797fd77d85cStructural control of InP/ZnS core/shell quantum dots enables high-quality white LEDsKumar, Baskaran Ganesh; Sadeghi, Sadra; Melikov, Rustamzhon; Aria, Mohammad Mohammadi; Jalali, Houman Bahmani; Ow-Yang, Cleva W.; Nizamoglu, SedatNanotechnology (2018), 29 (34), 345605/1-345605/9CODEN: NNOTER; ISSN:1361-6528. (IOP Publishing Ltd.)Herein, we demonstrate that the structural and optical control of InP-based quantum dots (QDs) can lead to high-performance light-emitting diodes (LEDs). Zinc sulfide (ZnS) shells passivate the InP QD core and increase the quantum yield in green-emitting QDs by 13-fold and redemitting QDs by 8-fold. The optimized QDs are integrated in the liq. state to eliminate aggregation-induced emission quenching and we fabricated white LEDs with a warm, neutral and cool-white appearance by the down-conversion mechanism. The QD-functionalized white LEDs achieve luminous efficiency (LE) up to 14.7 lmW-1 and color-rendering index up to 80. The structural and optical control of InP/ZnS core/shell QDs enable 23-fold enhancement in LE of white LEDs compared to ones contg. only QDs of InP core.
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147Achermann, M.; Petruska, M. A.; Crooker, S. A.; Klimov, V. I. Picosecond Energy Transfer in Quantum Dot Langmuir - Blodgett Nanoassemblies. J. Phys. Chem. B 2003, 107 (50), 13782– 13787, DOI: 10.1021/jp036497r147https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXptVKntL0%253D&md5=4e530b22ec2c71a4c74d6881c3905cc0Picosecond Energy Transfer in Quantum Dot Langmuir-Blodgett NanoassembliesAchermann, Marc; Petruska, Melissa A.; Crooker, Scott A.; Klimov, Victor I.Journal of Physical Chemistry B (2003), 107 (50), 13782-13787CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)The authors study spectrally resolved dynamics of Forster energy transfer in single monolayers and bilayers of semiconductor nanocrystal quantum dots assembled using Langmuir-Blodgett (LB) techniques. For a single monolayer, the authors observe a distribution of transfer times from ∼50 ps to ∼10 ns, which can be quant. modeled assuming that the energy transfer is dominated by interactions of a donor nanocrystal with acceptor nanocrystals from the 1st 3 shells surrounding the donor. The authors also detect an effective enhancement of the absorption cross section (up to a factor of 4) for larger nanocrystals on the red side of the size distribution, which results from strong, interdot electrostatic coupling in the LB film (the light-harvesting antenna effect). By assembling bilayers of nanocrystals of 2 different sizes, the authors are able to improve the donor-acceptor spectral overlap for engineered transfer in a specific (vertical) direction. These bilayers show a fast, unidirectional energy flow with a time const. of ∼120 ps.
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148Jin, F.; Zheng, M. L.; Liu, Z. H.; Fan, Y. M.; Xu, K.; Zhao, Z. S.; Duan, X. M. Layer-by-Layer Assembled PMMA-SH/CdSe-Au Nanocomposite Thin Films and the Optical Limiting Property. RSC Adv. 2016, 6 (30), 25401– 25408, DOI: 10.1039/C6RA02893D148https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XjsVeitLY%253D&md5=21ba426bdb55d5876fc3be605d7a444bLayer-by-layer assembled PMMA-SH/CdSe-Au nanocomposite thin films and the optical limiting propertyJin, Feng; Zheng, Mei-Ling; Liu, Zheng-Hui; Fan, Yi-Ming; Xu, Ke; Zhao, Zhen-Sheng; Duan, Xuan-MingRSC Advances (2016), 6 (30), 25401-25408CODEN: RSCACL; ISSN:2046-2069. (Royal Society of Chemistry)PMMA-SH/CdSe-Au nanocomposite thin films have been constructed by a layer-by-layer (LBL) assembly method. The LBL assembly process is carried out in a nonpolar solvent by the combination of photopolymn. and adsorption of CdSe-Au nanoparticles. Absorption spectra suggest that the LBL assembly is performed in a stepwise and uniform way. The optical, morphol., thermal, and optical limiting properties of the resultant PMMA-SH/CdSe-Au nanocomposite thin films are characterized by transmission, TEM, TGA and laser measurements. The LBL assembled PMMA-SH/CdSe-Au nanocomposite thin films exhibit good thermal stability, transparency, and optical limiting response to a 532 nm pulsed laser. The optical limiting threshold of the PMMA-SH/CdSe-Au nanocomposite thin film is 13 J cm-2. This study provides a robust and efficient strategy for fabricating transparent polymeric thin films with laser optical limiting property.
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149Nordlander, P.; Oubre, C.; Prodan, E.; Li, K.; Stockman, M. I. Plasmon Hybridization in Nanoparticle Dimers. Nano Lett. 2004, 4 (5), 899– 903, DOI: 10.1021/nl049681c149https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXjtVWjtb8%253D&md5=ea84018ef7760e1f23687ba25aaab488Plasmon Hybridization in Nanoparticle DimersNordlander, P.; Oubre, C.; Prodan, E.; Li, K.; Stockman, M. I.Nano Letters (2004), 4 (5), 899-903CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)The recently developed plasmon hybridization method was applied to nanoparticle dimers, providing a simple and intuitive description of how the energy and excitation cross sections of dimer plasmons depend on nanoparticle sepn. The dimer plasmons can be viewed as bonding and antibonding combinations, i.e., hybridization of the individual nanoparticle plasmons. The calcd. plasmon energies are compared with results from finite difference time domain simulations.
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150Borchert, H.; Haubold, S.; Haase, M.; Weller, H.; McGinley, C.; Riedler, M.; Möller, T. Investigation of ZnS Passivated InP Nanocrystals by XPS. Nano Lett. 2002, 2 (2), 151– 154, DOI: 10.1021/nl0156585150https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXovF2mur4%253D&md5=5ebc94aac466d061bae182ec64fd8608Investigation of ZnS Passivated InP Nanocrystals by XPSBorchert, Holger; Haubold, Stephan; Haase, Markus; Weller, Horst; McGinley, Colm; Riedler, Manfred; Moeller, ThomasNano Letters (2002), 2 (2), 151-154CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)ZnS passivated InP nanoparticles prepd. by the TOP/TOPO method have been investigated by photoelectron spectroscopy with tunable synchrotron radiation. Based on the energy dependence of the electron escape depth, we present a method to characterize the core-shell nature of the sample structure. Energy tuning indicates that In is confined to the core of the particles while Zn is located in a surrounding shell. Computer simulation allows us to quantify these results and to ext. av. layer thicknesses.
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151Şahin, M.; Nizamoglu, S.; Kavruk, A. E.; Demir, H. V. Self-Consistent Computation of Electronic and Optical Properties of a Single Exciton in a Spherical Quantum Dot via Matrix Diagonalization Method. J. Appl. Phys. 2009, 106 (4), 043704, DOI: 10.1063/1.3197034151https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVeqt7bF&md5=e447a60dda5fa07a2f69f495b18b780fSelf-consistent computation of electronic and optical properties of a single exciton in a spherical quantum dot via matrix diagonalization methodSahin, Mehmet; Nizamoglu, Sedat; Kavruk, A. Emre; Demir, Hilmi VolkanJournal of Applied Physics (2009), 106 (4), 043704/1-043704/5CODEN: JAPIAU; ISSN:0021-8979. (American Institute of Physics)In this study, we develop and demonstrate an efficient self-consistent calcn. schema that computes the electronic structure and optical properties of a single exciton in a spherical quantum dot (QD) with an interacting pair of electron and hole wave functions. To observe modifications on bands, wave functions, and energies due to the attractive Coulomb potential, the full numeric matrix diagonalization technique is employed to det. sublevel energy eigenvalues and their wave functions in effective mass approxn. This treatment allows to observe that the conduction and valence band edges bend, that the electron and hole wave functions strongly localize in the QD, and that the excitonic energy level exhibits red shift. In our approach for the Coulomb term between electron and hole, the Poisson-Schroedinger equations are solved self-consistently in the Hartree approxn. Subsequently, exciton binding energies and assocd. optical properties are computed. The results are presented as a function of QD radii and photon energies. We conclude that all of these numerical results are in agreement with the exptl. studies. (c) 2009 American Institute of Physics.
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152Gong, X.; Tong, M.; Brunetti, F. G.; Seo, J.; Sun, Y.; Moses, D.; Wudl, F.; Heeger, A. J. Bulk Heterojunction Solar Cells with Large Open-Circuit Voltage: Electron Transfer with Small Donor-Acceptor Energy Offset. Adv. Mater. 2011, 23 (20), 2272– 2277, DOI: 10.1002/adma.201003768152https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXms1SktLs%253D&md5=a0730c4fed90fb7562515e800e738e9dBulk Heterojunction Solar Cells with Large Open-Circuit Voltage and Electron Transfer with Small Donor-Acceptor Energy OffsetGong, Xiong; Tong, Minghong; Brunetti, Fulvio G.; Seo, Junghwa; Sun, Yanming; Moses, Daniel; Wudl, Fred; Heeger, Alan J.Advanced Materials (Weinheim, Germany) (2011), 23 (20), 2272-2277CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)The authors characterized the new electron acceptor D99'BF and the P3HT:D99'BF bulk heterojunction (BHJ) material, showing that D99'BF exhibits strong optical absorption over the spectral range from 4 eV to 1.9 eV, and increases the optical d. and improves the light harvesting in this spec-tral range when it is blended with P3HT. Ultrafast charge transfer and charge sepn. are demonstrated in P3HT:D99'BF BHJ films, and photoinduced electron transfer from P3HT to the D99'BF yields mobile carriers with long lifetimes. It was demonstrated that electron transfer occurs even though ELUMO(P3HT)-ELUMO(D99'BF) = 0.12 eV. indicating that large LUMO band offsets are not required for charge sepn., and the exciton binding energy in P3HT must be less than approx. 0.1 eV. BHJ PSCs fabricated using P3HT:D99'BF phase sepd. composites exhibit an open circuit voltage, Voc = 1.20 V (under AM 1.5 solar radiation), close to the theor. max. estd. from the difference in the energy levels of the HOMO of P3HT and LUMO of D99'BF, indicating that Voc values close to the band gap of the semiconducting polymer should be possible for BHJ PSCs just as for inorg. solar cells.
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153Cao, Y.; Stavrinadis, A.; Lasanta, T.; So, D.; Konstantatos, G. The Role of Surface Passivation for Efficient and Photostable PbS Quantum Dot Solar Cells. Nat. Energy 2016, 1 (4), 16035, DOI: 10.1038/nenergy.2016.35153https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhtVekurk%253D&md5=e0ffcf8f062cb920cc708d564109e047The role of surface passivation for efficient and photostable PbS quantum dot solar cellsCao, Yiming; Stavrinadis, Alexandros; Lasanta, Tania; So, David; Konstantatos, GerasimosNature Energy (2016), 1 (4), 16035CODEN: NEANFD; ISSN:2058-7546. (Nature Publishing Group)For any emerging photovoltaic technol. to become com. relevant, both its power conversion efficiency and photostability are key parameters to be fulfilled. Colloidal quantum dot solar cells are a soln.-processed, low-cost technol. that has reached an efficiency of about 9% by judiciously controlling the surface of the quantum dots to enable surface passivation and tune energy levels. However, the role of the quantum dot surface on the stability of these solar cells has remained elusive. Here we report on highly efficient and photostable quantum dot solar cells with efficiencies of 9.6% (and independently certificated values of 8.7%). As a result of optimized surface passivation and the suppression of hydroxyl ligands-which are found to be detrimental for both efficiency and photostability-the efficiency remains within 80% of its initial value after 1,000 h of continuous illumination at AM1.5G. Our findings provide insights into the role of the quantum dot surface in both the stability and efficiency of quantum dot solar cells.
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154Durmusoglu, E. G.; Selopal, G. S.; Mohammadnezhad, M.; Zhang, H.; Dagtepe, P.; Barba, D.; Sun, S.; Zhao, H.; Acar, H. Y.; Wang, Z. M.; Rosei, F. Low-Cost, Air-Processed Quantum Dot Solar Cells via Diffusion-Controlled Synthesis. ACS Appl. Mater. Interfaces 2020, 12 (32), 36301– 36310, DOI: 10.1021/acsami.0c06694154https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtl2jur%252FE&md5=787c9bc3937e38f8228bddc38d59541cLow-Cost, Air-Processed Quantum Dot Solar Cells via Diffusion-Controlled SynthesisDurmusoglu, Emek G.; Selopal, Gurpreet S.; Mohammadnezhad, Mahyar; Zhang, Hui; Dagtepe, Pinar; Barba, David; Sun, Shuhui; Zhao, Haiguang; Acar, Havva Yagci; Wang, Zhiming M.; Rosei, FedericoACS Applied Materials & Interfaces (2020), 12 (32), 36301-36310CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Despite significant advances in the development of high-efficiency and stable quantum dot (QD) solar cells (QDSCs), recent synthetic and fabrication routes still require improvements to render QDSCs com. feasible. Here, we describe a low-cost, industrially viable fabrication method of QDSCs under an ambient atm. (humid air and room temp.) using stable, high-quality, and small-sized PbS QDs prepd. with low-cost, greener precursors [i.e., thioacetamide (TAA)] compared to the widely used bis(trimethylsilyl)sulfide [(TMS)2S], at low temps. without requiring any stringent conditions. The low reaction temp., medium reactivity of TAA, and diffusion-controlled particle growth adopted in this approach provide an opportunity to synthesize ultrasmall (emission peak ~ 700 nm) to larger PbS QDs (emission peak ~ 1050 nm). This also enables well-controlled large-scale (multigram) synthesis with a rough estd. prodn. cost of PbS of 8.11 $ per g (based on materials cost), which is the lowest among the available PbS QDs produced using wet chem. routes. QDSCs fabricated using 3.25 nm PbS QDs (bandgap 1.29 eV) under ambient conditions yield a high circuit c.d. (Jsc) of 32.4 mA/cm2 (one of the highest values of Jsc ever reported) with a power conversion efficiency of 7.8% under 1 sun simulated sunlight at AM 1.5 G (100 mW/cm2). These devices exhibit better photovoltaic performance compared to devices fabricated with more traditional PbS QDs synthesized with (TMS)2S under an ambient atm., confirming the quality of PbS QDs produced with our method. The diffusion-controlled TAA-based synthetic route developed herein is found to be very promising for synthesizing size-tunable PbS QDs for photovoltaic and other optoelectronic applications.
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155Corna, A.; Herrmann, T.; Zeck, G. Electrode-Size Dependent Thresholds in Subretinal Neuroprosthetic Stimulation. J. Neural Eng. 2018, 15 (4), 045003, DOI: 10.1088/1741-2552/aac1c8155https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MjovFaitA%253D%253D&md5=bb689e644e0098843cd7edc18a853e81Electrode-size dependent thresholds in subretinal neuroprosthetic stimulationCorna Andrea; Herrmann Thoralf; Zeck GuntherJournal of neural engineering (2018), 15 (4), 045003 ISSN:.OBJECTIVE: Retinal prostheses have shown promising results in restoring some visual perception to blind patients but successful identification of objects of different size remains a challenge. Here we investigated electrode-size specific stimulation thresholds and their variability for subretinal electrical stimulation. Our findings indicate the range of charge densities required to achieve identification of small objects and the object-size-specific scaling of stimulation threshold. APPROACH: Using biphasic voltage-limited current stimuli provided by a light-sensitive microchip, we determined threshold charge densities for stimulation with variable electrode sizes. The stimulated activation of the retinal network was identified by recording the spiking of retinal ganglion cells in photoreceptor-degenerated mouse rd10 retinas. Stimulation thresholds were determined for cells with saturating stimulus response relationships (SRRs) but not for cells characterized by monotonically increasing or decreasing SRRs. MAIN RESULTS: Stimulation thresholds estimated in rd10 retinas ranged between 100-900 μC cm(-2) for stimulation with small electrodes (30 μm diameter). Threshold charge density decreased with increasing electrode size and plateaued at 20 μC cm(-2) for an electrode diameter larger than 300 μm. This trend of decreasing threshold down to a plateau value was confirmed in wild-type mouse retina suggesting an underlying physiological source. SIGNIFICANCE: Our results suggest the following guidelines for retinal prosthetics employing biphasic current pulses. The encoding of small objects may be achieved through the activation of a confined set of different retinal ganglion cells, with individual stimulation thresholds spanning a wide range of charge densities. The encoding of increasing object sizes may be achieved by decreasing stimulation charge density.
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156Bahmani Jalali, H.; Sadeghi, S.; Sahin, M.; Ozturk, H.; Ow-Yang, C. W.; Nizamoglu, S. Colloidal Aluminum Antimonide Quantum Dots. Chem. Mater. 2019, 31 (13), 4743– 4747, DOI: 10.1021/acs.chemmater.9b00905156https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtFaqtrnE&md5=a1d505509f3bfd0c89a64bc2e0f00fa1Colloidal Aluminum Antimonide Quantum DotsBahmani Jalali, Houman; Sadeghi, Sadra; Sahin, Mehmet; Ozturk, Hande; Ow-Yang, Cleva W.; Nizamoglu, SedatChemistry of Materials (2019), 31 (13), 4743-4747CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)AlSb is a less studied member of the III-V semiconductor family, and herein, we report the colloidal synthesis of AlSb quantum dots (QDs) for the first time. Different sizes of colloidal AlSb QDs (5 to 9 nm) were produced by the controlled reaction of AlCl3 and Sb[N(Si(Me)3)2]3 in the presence of superhydride. These colloidal AlSb quantum dots showed excitonic transitions in the UV-A region and a tunable band-edge emission (quantum yield of up to 18%) in the blue spectral range. Among all III-V quantum dots, these quantum dots show the brightest core emission in the blue spectral region.
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157Linnebach, R.; Benz, K. W. Bridgman Growth of AlSb. J. Cryst. Growth 1981, 53 (3), 579– 585, DOI: 10.1016/0022-0248(81)90142-1157https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL3MXksFartLw%253D&md5=cf85e1ef72a4e563050ca6f75e53ce8fBridgman growth of aluminum antimonideLinnebach, R.; Benz, K. W.Journal of Crystal Growth (1981), 53 (3), 579-85CODEN: JCRGAE; ISSN:0022-0248.Crystals of undoped AlSb were grown from Sb-rich solns. at temps. < 1250 K using the Bridgman method. C crucibles inserted in sealed silica ampuls filled with Ar at low pressure gave the best results. High resistivity (ρ ≃ 200-600 Ω-cm) polycryst. material without any voids could be synthesized. Crystals grown at low temp. were particularly resistant to corrosion. Schottky barriers with reverse currents of < 0.5 μA/mm2 at 1 V could be prepd. in undoped p-type AlSb.
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158Schwartz, G. P.; Gualtieri, G. J.; Sunder, W. A.; Farrow, L. A. Light Scattering from Quantum Confined and Interface Optical Vibrational Modes in Strained-Layer GaSb/AlSb Superlattices. Phys. Rev. B 1987, 36 (9), 4868– 4877, DOI: 10.1103/PhysRevB.36.4868158https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2sXmtVOrs7s%253D&md5=9724b96b84d81afa715d88eeaea26805Light scattering from quantum confined and interface optical vibrational modes in strained-layer gallium antimonide/aluminum antimonide superlatticesSchwartz, G. P.; Gualtieri, G. J.; Sunder, W. A.; Farrow, L. A.Physical Review B: Condensed Matter and Materials Physics (1987), 36 (9), 4868-77CODEN: PRBMDO; ISSN:0163-1829.Raman scattering was performed on GaSb/AlSb strained-layer superlattices with periods varying from 65 to 300 Å. Discrete quantum confined GaSb longitudinal optical phonons were obsd. in GaSb layers at <25 Å thick. The confinement-induced Γ-to-L crossover in GaSb manifests itself in the spectra via the observation of optical-phonon d.-of-states structure. This structure disappears for GaSb layers thicker than 50 Å. Spatially extended interface modes were obsd. in all superlattices in both the GaSb and AlSb optical-mode spectra.
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159Barate, D.; Teissier, R.; Wang, Y.; Baranov, A. N. Short Wavelength Intersubband Emission from InAs/AlSb Quantum Cascade Structures. Appl. Phys. Lett. 2005, 87 (5), 051103, DOI: 10.1063/1.2007854159https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXnvVSnur0%253D&md5=599d631e809721fee580c8d6cffb0cc7Short wavelength intersubband emission from InAs/AlSb quantum cascade structuresBarate, D.; Teissier, R.; Wang, Y.; Baranov, A. N.Applied Physics Letters (2005), 87 (5), 051103/1-051103/3CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The InAs/AlSb material system is a promising candidate for the development of short wavelength quantum cascade lasers because of the large conduction band offset of 2.1 eV. The authors present a study of room temp. electroluminescence of InAs/AlSb quantum cascade structures as a function of the emission wavelength. Intersubband emission with a transition energy of 500 meV (λ=2.5 μm) was obtained.
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160Classen, A.; Chochos, C. L.; Lüer, L.; Gregoriou, V. G.; Wortmann, J.; Osvet, A.; Forberich, K.; McCulloch, I.; Heumüller, T.; Brabec, C. J. The Role of Exciton Lifetime for Charge Generation in Organic Solar Cells at Negligible Energy-Level Offsets. Nat. Energy 2020, 5 (9), 711– 719, DOI: 10.1038/s41560-020-00684-7160https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhvF2ksrjM&md5=e0217198005d63dc8e92e64031ba6f25The role of exciton lifetime for charge generation in organic solar cells at negligible energy-level offsetsClassen, Andrej; Chochos, Christos L.; Lueer, Larry; Gregoriou, Vasilis G.; Wortmann, Jonas; Osvet, Andres; Forberich, Karen; McCulloch, Iain; Heumueller, Thomas; Brabec, Christoph J.Nature Energy (2020), 5 (9), 711-719CODEN: NEANFD; ISSN:2058-7546. (Nature Research)Org. solar cells utilize an energy-level offset to generate free charge carriers. Although a very small energy-level offset increases the open-circuit voltage, it remains unclear how exactly charge generation is affected. Here we investigate org. solar cell blends with HOMO energy-level offsets (ΔEHOMO) between the donor and acceptor that range from 0 to 300 meV. We demonstrate that exciton quenching at a negligible ΔEHOMO takes place on timescales that approach the exciton lifetime of the pristine materials, which drastically limits the external quantum efficiency. We quant. describe this finding via the Boltzmann stationary-state equil. between charge-transfer states and excitons and further reveal a long exciton lifetime to be decisive in maintaining an efficient charge generation at a negligible ΔEHOMO. Moreover, the Boltzmann equil. quant. describes the major redn. in non-radiative voltage losses at a very small ΔEHOMO. Ultimately, highly luminescent near-IR emitters with very long exciton lifetimes are suggested to enable highly efficient org. solar cells.
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161Melikov, R.; Srivastava, S. B.; Karatum, O.; Dogru-Yuksel, I. B.; Bahmani Jalali, H.; Sadeghi, S.; Dikbas, U. M.; Ulgut, B.; Kavakli, I. H.; Cetin, A. E.; Nizamoglu, S. Plasmon-Coupled Photocapacitor Neuromodulators. ACS Appl. Mater. Interfaces 2020, 12 (32), 35940– 35949, DOI: 10.1021/acsami.0c09455161https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXhtl2rs7vJ&md5=dfca3d90ace51d08ca8bbec90a9827f3Plasmon-Coupled Photocapacitor NeuromodulatorsMelikov, Rustamzhon; Srivastava, Shashi Bhushan; Karatum, Onuralp; Dogru-Yuksel, Itir Bakis; Bahmani Jalali, Houman; Sadeghi, Sadra; Dikbas, Ugur Meric; Ulgut, Burak; Kavakli, Ibrahim Halil; Cetin, Arif E.; Nizamoglu, SedatACS Applied Materials & Interfaces (2020), 12 (32), 35940-35949CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Efficient transduction of optical energy to bioelec. stimuli is an important goal for effective communication with biol. systems. For that, plasmonics has a significant potential via boosting the light-matter interactions. However, plasmonics has been primarily used for heat-induced cell stimulation due to membrane capacitance change (i.e., optocapacitance). Instead, here, we demonstrate that plasmonic coupling to photocapacitor biointerfaces improves safe and efficacious neuromodulating displacement charges for an av. of 185% in the entire visible spectrum while maintaining the faradic currents below 1%. Hot-electron injection dominantly leads the enhancement of displacement current in the blue spectral window, and the nanoantenna effect is mainly responsible for the improvement in the red spectral region. The plasmonic photocapacitor facilitates wireless modulation of single cells at three orders of magnitude below the max. retinal intensity levels, corresponding to one of the most sensitive optoelectronic neural interfaces. This study introduces a new way of using plasmonics for safe and effective photostimulation of neurons and paves the way toward ultrasensitive plasmon-assisted neurostimulation devices.
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162Kesim, C.; Han, M.; Yildiz, E.; Bahmani Jalali, H.; Qureshi, M. H.; Hasanreisoglu, M.; Nizamoglu, S.; Sahin, A. Biocompatibility and Neural Stimulation Capacity of Aluminum Antimonide Nanocrystals Biointerfaces for Use in Artificial Vision. Invest. Ophthalmol. Vis. Sci. 2021, 62 (8), 3217There is no corresponding record for this reference.
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163Jaiswal, J. K.; Mattoussi, H.; Mauro, J. M.; Simon, S. M. Long-Term Multiple Color Imaging of Live Cells Using Quantum Dot Bioconjugates. Nat. Biotechnol. 2003, 21 (1), 47– 51, DOI: 10.1038/nbt767163https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXhvVyq&md5=fa97be979d4d5fae784e7239cb6a164eLong-term multiple color imaging of live cells using quantum dot bioconjugatesJaiswal, Jyoti K.; Mattoussi, Hedi; Mauro, J. Matthew; Simon, Sanford M.Nature Biotechnology (2003), 21 (1), 47-51CODEN: NABIF9; ISSN:1087-0156. (Nature Publishing Group)Luminescent quantum dots (QDs)-semiconductor nanocrystals-are a promising alternative to org. dyes for fluorescence-based applications. We have developed procedures for using QDs to label live cells and have demonstrated their use for long-term multicolor imaging of live cells. The two approaches presented are (i) endocytic uptake of QDs and (ii) selective labeling of cell surface proteins with QDs conjugated to antibodies. Live cells labeled using these approaches were used for long-term multicolor imaging. The cells remained stably labeled for over a week as they grew and developed. These approaches should permit the simultaneous study of multiple cells over long periods of time as they proceed through growth and development.
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164Derfus, A. M.; Chan, W. C. W.; Bhatia, S. N. Probing the Cytotoxicity of Semiconductor Quantum Dots. Nano Lett. 2004, 4 (1), 11– 18, DOI: 10.1021/nl0347334164https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXps1SmtLo%253D&md5=c5953773f4169b5256f0fdb7d53fee08Probing the Cytotoxicity of Semiconductor Quantum DotsDerfus, Austin M.; Chan, Warren C. W.; Bhatia, Sangeeta N.Nano Letters (2004), 4 (1), 11-18CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)With their bright, photostable fluorescence, semiconductor quantum dots (QDs) show promise as alternatives to org. dyes for biol. labeling. Questions about their potential cytotoxicity, however, remain unanswered. While cytotoxicity of bulk cadmium selenide (CdSe) is well documented, a no. of groups have suggested that CdSe QDs are cytocompatible, at least with some immortalized cell lines. Using primary hepatocytes as a liver model, we found that CdSe-core QDs were indeed acutely toxic under certain conditions. Specifically, we found that the cytotoxicity of QDs was modulated by processing parameters during synthesis, exposure to UV light, and surface coatings. Our data further suggest that cytotoxicity correlates with the liberation of free Cd2+ ions due to deterioration of the CdSe lattice. When appropriately coated, CdSe-core QDs can be rendered nontoxic and used to track cell migration and reorganization in vitro. Our results provide information for design criteria for the use of QDs in vitro and esp. in vivo, where deterioration over time may occur.
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165Rosenthal, S. J.; Chang, J. C.; Kovtun, O.; McBride, J. R.; Tomlinson, I. D. Biocompatible Quantum Dots for Biological Applications. Chem. Biol. 2011, 18 (1), 10– 24, DOI: 10.1016/j.chembiol.2010.11.013165https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlaku7Y%253D&md5=665dbadc6d8f33b993e285bed85586a8Biocompatible Quantum Dots for Biological ApplicationsRosenthal, Sandra J.; Chang, Jerry C.; Kovtun, Oleg; McBride, James R.; Tomlinson, Ian D.Chemistry & Biology (Cambridge, MA, United States) (2011), 18 (1), 10-24CODEN: CBOLE2; ISSN:1074-5521. (Cell Press)A review. Semiconductor quantum dots are quickly becoming a crit. diagnostic tool for discerning cellular function at the mol. level. Their high brightness, long-lasting, size-tunable, and narrow luminescence set them apart from conventional fluorescence dyes. Quantum dots are being developed for a variety of biol. oriented applications, including fluorescent assays for drug discovery, disease detection, single protein tracking, and intracellular reporting. This review introduces the science behind quantum dots and describes how they are made biol. compatible. Several applications are also included, illustrating strategies toward target specificity, and are followed by a discussion on the limitations of quantum dot approaches. The article is concluded with a look at the future direction of quantum dots.
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166Gao, X.; Chan, W. C. W.; Nie, S. Quantum-Dot Nanocrystals for Ultrasensitive Biological Labeling and Multicolor Optical Encoding. J. Biomed. Opt. 2002, 7 (4), 532, DOI: 10.1117/1.1506706166https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38XotFyqsLk%253D&md5=222984987fb11bc8e4926feb27571243Quantum-dot nanocrystals for ultrasensitive biological labeling and multicolor optical encodingGao, Xiaohu; Chan, Warren C. W.; Nie, ShumingJournal of Biomedical Optics (2002), 7 (4), 532-537CODEN: JBOPFO; ISSN:1083-3668. (SPIE-The International Society for Optical Engineering)Semiconductor nanoparticles in the size range of 2-6 nm are of great current interest, not only because of their size-tunable properties but also because of their dimensional similarity with biol. macromols. (e.g., nucleic acids and proteins). This similarity could allow an integration of nanomaterials with biol. mols., which would have applications in medical diagnostics, targeted therapeutics, and high-throughput drug screening. Here we report new developments in prepg. highly luminescent and biocompatible CdSe quantum dots (QDs), and in synthesizing QD-encoded micro- and nano-beads in the size range of 100 nm-10 μm. We show that the optical properties of ZnS-capped CdSe quantum dots are sensitive to environmental factors such as pH and divalent cations, leading to the potential use of quantum dots in mol. sensing. We also show that chem. modified proteins can be used to coat the surface of water-sol. QDs, to restore their fluorescence, and to provide functional groups for bioconjugation. For multiplexed optical encoding, we have prepd. large microbeads with sizes similar to that of mammalian cells, and small nanobeads with sizes similar to that of viruses.
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167Devatha, G.; Roy, S.; Rao, A.; Mallick, A.; Basu, S.; Pillai, P. P. Electrostatically Driven Resonance Energy Transfer in “Cationic” Biocompatible Indium Phosphide Quantum Dots. Chem. Sci. 2017, 8 (5), 3879– 3884, DOI: 10.1039/C7SC00592J167https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXktFykur8%253D&md5=4258e94b7eb9012b952b3e7c6aab42d8Electrostatically driven resonance energy transfer in "cationic" biocompatible indium phosphide quantum dotsDevatha, Gayathri; Roy, Soumendu; Rao, Anish; Mallick, Abhik; Basu, Sudipta; Pillai, Pramod P.Chemical Science (2017), 8 (5), 3879-3884CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)Indium Phosphide Quantum Dots (InP QDs) have emerged as an alternative to toxic metal ion based QDs in nanobiotechnol. The ability to generate cationic surface charge, without compromising stability and biocompatibility, is essential in realizing the full potential of InP QDs in biol. applications. We have addressed this challenge by developing a place exchange protocol for the prepn. of cationic InP/ZnS QDs. The quaternary ammonium group provides the much required permanent pos. charge and stability to InP/ZnS QDs in biofluids. The two important properties of QDs, namely bioimaging and light induced resonance energy transfer, are successfully demonstrated in cationic InP/ZnS QDs. The low cytotoxicity and stable photoluminescence of cationic InP/ZnS QDs inside cells make them ideal candidates as optical probes for cellular imaging. An efficient resonance energy transfer (E ∼ 60%) is obsd., under physiol. conditions, between the cationic InP/ZnS QD donor and anionic dye acceptor. A large bimol. quenching const. along with a linear Stern-Volmer plot confirms the formation of a strong ground state complex between the cationic InP/ZnS QDs and the anionic dye. Control expts. prove the role of electrostatic attraction in driving the light induced interactions, which can rightfully form the basis for future nano-bio studies between cationic InP/ZnS QDs and anionic biomols.
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168Chen, L.-D.; Liu, J.; Yu, X.-F.; He, M.; Pei, X.-F.; Tang, Z.-Y.; Wang, Q.-Q.; Pang, D.-W.; Li, Y. The Biocompatibility of Quantum Dot Probes Used for the Targeted Imaging of Hepatocellular Carcinoma Metastasis. Biomaterials 2008, 29 (31), 4170– 4176, DOI: 10.1016/j.biomaterials.2008.07.025168https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVaju7jL&md5=619d04d17ac0436a69941cd93a1c5577The biocompatibility of quantum dot probes used for the targeted imaging of hepatocellular carcinoma metastasisChen, Liang-Dong; Liu, Jia; Yu, Xue-Feng; He, Man; Pei, Xiao-Feng; Tang, Zhao-You; Wang, Qu-Quan; Pang, Dai-Wen; Li, YanBiomaterials (2008), 29 (31), 4170-4176CODEN: BIMADU; ISSN:0142-9612. (Elsevier Ltd.)Semiconductor quantum dots (QDs) have several photo-phys. advantages over org. dyes making them good markers in biomedical application. We used CdSe/ZnS QDs with max. emission wavelength of 590 nm (QD590) linked to alpha-fetoprotein (AFP) monoclonal antibody (Ab) to detect AFP in cytoplasm of human hepatocellular carcinoma (HCC) cell line HCCLM6. For the in vivo studies, we used QD-AFP-Ab probes for targeted imaging of human HCC xenograft growing in nude mice by injecting them into the tail vein. In addn., the cytotoxicity in vitro, the acute toxicity in vivo, the hemodynamics and tissue distribution of these probes were also investigated. The results in vitro and in vivo indicate that our QD-based probes have good stability, specificity and biocompatibility for ultrasensitive fluorescence imaging of mol. targets in our liver cancer model system.
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169Cogan, S. F.; Ludwig, K. A.; Welle, C. G.; Takmakov, P. Tissue Damage Thresholds during Therapeutic Electrical Stimulation. J. Neural Eng. 2016, 13 (2), 021001, DOI: 10.1088/1741-2560/13/2/021001169https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28nivVSltw%253D%253D&md5=8804003dcd9fca783a975b2c6f87c220Tissue damage thresholds during therapeutic electrical stimulationCogan Stuart F; Ludwig Kip A; Welle Cristin G; Takmakov PavelJournal of neural engineering (2016), 13 (2), 021001 ISSN:.OBJECTIVE: Recent initiatives in bioelectronic modulation of the nervous system by the NIH (SPARC), DARPA (ElectRx, SUBNETS) and the GlaxoSmithKline Bioelectronic Medicines effort are ushering in a new era of therapeutic electrical stimulation. These novel therapies are prompting a re-evaluation of established electrical thresholds for stimulation-induced tissue damage. APPROACH: In this review, we explore what is known and unknown in published literature regarding tissue damage from electrical stimulation. MAIN RESULTS: For macroelectrodes, the potential for tissue damage is often assessed by comparing the intensity of stimulation, characterized by the charge density and charge per phase of a stimulus pulse, with a damage threshold identified through histological evidence from in vivo experiments as described by the Shannon equation. While the Shannon equation has proved useful in assessing the likely occurrence of tissue damage, the analysis is limited by the experimental parameters of the original studies. Tissue damage is influenced by factors not explicitly incorporated into the Shannon equation, including pulse frequency, duty cycle, current density, and electrode size. Microelectrodes in particular do not follow the charge per phase and charge density co-dependence reflected in the Shannon equation. The relevance of these factors to tissue damage is framed in the context of available reports from modeling and in vivo studies. SIGNIFICANCE: It is apparent that emerging applications, especially with microelectrodes, will require clinical charge densities that exceed traditional damage thresholds. Experimental data show that stimulation at higher charge densities can be achieved without causing tissue damage, suggesting that safety parameters for microelectrodes might be distinct from those defined for macroelectrodes. However, these increased charge densities may need to be justified by bench, non-clinical or clinical testing to provide evidence of device safety.
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170Brocker, D. T.; Grill, W. M. Principles of Electrical Stimulation of Neural Tissue. In Handbook of Clinical Neurology; Lozano, A. M., Hallett, M., Eds.; Elsevier, 2013; Vol. 116, pp 3– 18. DOI: 10.1016/B978-0-444-53497-2.00001-2There is no corresponding record for this reference.
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171Rizzo III, J. F.; Wyatt, J.; Loewenstein, J.; Kelly, S.; Shire, D. Methods and Perceptual Thresholds for Short-Term Electrical Stimulation of Human Retina with Microelectrode Arrays. Invest. Ophthalmol. Vis. Sci. 2003, 44 (12), 5355– 5361, DOI: 10.1167/iovs.02-0819There is no corresponding record for this reference.
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172Butterwick, A. F.; Vankov, A.; Huie, P.; Palanker, D. V. Dynamic Range of Safe Electrical Stimulation of the Retina. Ophthalmic Technologies XVI 2006, 6138, 61380Q, DOI: 10.1117/12.650652There is no corresponding record for this reference.
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173Zhang, J.; Tang, Y.; Lee, K.; Ouyang, M. Nonepitaxial Growth of Hybrid Core-Shell Nanostructures with Large Lattice Mismatches. Science (80-.). 2010, 327 (5973), 1634– 1638, DOI: 10.1126/science.1184769There is no corresponding record for this reference.
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174Sadeghi, S.; Melikov, R.; Sahin, M.; Nizamoglu, S. Cation Exchange Mediated Synthesis of Bright Au@ZnTe Core-Shell Nanocrystals. Nanotechnology 2021, 32 (2), 025603, DOI: 10.1088/1361-6528/abbb02174https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXit1KmurrJ&md5=7181405fb2dda23386105b45d96db3f1Cation exchange mediated synthesis of bright Au@ZnTe core-shell nanocrystalsSadeghi, Sadra; Melikov, Rustamzhon; Sahin, Mehmet; Nizamoglu, SedatNanotechnology (2021), 32 (2), 025603CODEN: NNOTER; ISSN:1361-6528. (IOP Publishing Ltd.)The synthesis of heterostructured core-shell nanocrystals has attracted significant attention due to their wide range of applications in energy, medicine and environment. To further extend the possible nanostructures, non-epitaxial growth is introduced to form heterostructures with large lattice mismatches, which cannot be achieved by classical epitaxial growth techniques. Here, we report the synthetic procedure of Au@ZnTe core-shell nanostructures by cation exchange reaction for the first time. For that, bimetallic Au@Ag heterostructures were synthesized by using PDDA as stabilizer and shape-controller. Then, by addn. of Te and Zn precursors in a step-wise reaction, the zinc and silver cation exchange was performed and Au@ZnTe nanocrystals were obtained. Structural and optical characterization confirmed the formation of the Au@ZnTe nanocrystals. The optimization of the synthesis led to the bright nanocrystals with a photoluminescence quantum yield up to 27%. The non-toxic, versatile synthetic route, and bright emission of the synthesized Au@ZnTe nanocrystals offer significant potential for future bio-imaging and optoelectronic applications.
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175Zhang, Y.; Zhu, X.; Zhang, Y. Exploring Heterostructured Upconversion Nanoparticles: From Rational Engineering to Diverse Applications. ACS Nano 2021, 15 (3), 3709– 3735, DOI: 10.1021/acsnano.0c09231175https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXlvVKktbo%253D&md5=95749020a6713f3147a568c73dd92923Exploring Heterostructured Upconversion Nanoparticles: From Rational Engineering to Diverse ApplicationsZhang, Yi; Zhu, Xiaohui; Zhang, YongACS Nano (2021), 15 (3), 3709-3735CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)A review. Upconversion nanoparticles (UCNPs) represent a class of optical nanomaterials that can convert low-energy excitation photons to high-energy fluorescence emissions. From UCNPs, heterostructured UCNPs, consisting of UCNPs and other functional counterparts (metals, semiconductors, polymers, etc.), present an intriguing system in which the physicochem. properties are largely influenced by the entire assembled particle and also by the morphol., dimension, and compn. of each individual component. As multicomponent nanomaterials, heterostructured UCNPs can overcome challenges assocd. with a single component and exhibit bifunctional or multifunctional properties, which can further expand their applications in bioimaging, biodetection, and phototherapy. In this review, the authors provide a summary of recent achievements in the field of heterostructured UCNPs in the aspects of construction strategies, synthetic approaches, and types of heterostructured UCNPs. This review also summarizes the trends in biomedical applications of heterostructured UCNPs and discusses the challenges and potential solns. in this field.
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176Wu, X.; Zhang, Y.; Takle, K.; Bilsel, O.; Li, Z.; Lee, H.; Zhang, Z.; Li, D.; Fan, W.; Duan, C.; Chan, E. M.; Lois, C.; Xiang, Y.; Han, G. Dye-Sensitized Core/Active Shell Upconversion Nanoparticles for Optogenetics and Bioimaging Applications. ACS Nano 2016, 10 (1), 1060– 1066, DOI: 10.1021/acsnano.5b06383176https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XjvFeisg%253D%253D&md5=3d945e6f3ca91b8d8d9ed96d0b825b9cDye-Sensitized Core/Active Shell Upconversion Nanoparticles for Optogenetics and Bioimaging ApplicationsWu, Xiang; Zhang, Yuanwei; Takle, Kendra; Bilsel, Osman; Li, Zhanjun; Lee, Hyungseok; Zhang, Zijiao; Li, Dongsheng; Fan, Wei; Duan, Chunying; Chan, Emory M.; Lois, Carlos; Xiang, Yang; Han, GangACS Nano (2016), 10 (1), 1060-1066CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Near-IR (NIR) dye-sensitized upconversion nanoparticles (UCNPs) can broaden the absorption range and boost upconversion efficiency of UCNPs. Here, we achieved significantly enhanced upconversion luminescence in dye-sensitized core/active shell UCNPs via the doping of ytterbium ions (Yb3+) in the UCNP shell, which bridged the energy transfer from the dye to the UCNP core. As a result, we synergized the two most practical upconversion booster effectors (dye-sensitizing and core/shell enhancement) to amplify upconversion efficiency. We demonstrated two biomedical applications using these UCNPs. By using dye-sensitized core/active shell UCNP embedded poly(Me methacrylate) polymer implantable systems, we successfully shifted the optogenetic neuron excitation window to a biocompatible and deep tissue penetrable 800 nm wavelength. Furthermore, UCNPs were water-solubilized with Pluronic F127 with high upconversion efficiency and can be imaged in a mouse model.
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177Lin, X.; Chen, X.; Zhang, W.; Sun, T.; Fang, P.; Liao, Q.; Chen, X.; He, J.; Liu, M.; Wang, F.; Shi, P. Core-Shell-Shell Upconversion Nanoparticles with Enhanced Emission for Wireless Optogenetic Inhibition. Nano Lett. 2018, 18 (2), 948– 956, DOI: 10.1021/acs.nanolett.7b04339177https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXitVeltL7L&md5=275e099037653df567929d4fdf9c107eCore-Shell-Shell Upconversion Nanoparticles with Enhanced Emission for Wireless Optogenetic InhibitionLin, Xudong; Chen, Xian; Zhang, Wenchong; Sun, Tianying; Fang, Peilin; Liao, Qinghai; Chen, Xi; He, Jufang; Liu, Ming; Wang, Feng; Shi, PengNano Letters (2018), 18 (2), 948-956CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Recent advances in upconversion technol. have enabled optogenetic neural stimulation using remotely applied optical signals, but limited success was demonstrated for neural inhibition by using this method, primarily due to the much higher optical power and more red-shifted excitation spectrum that are required to work with the appropriate inhibitory opsin proteins. To overcome these limitations, core-shell-shell upconversion nanoparticles (UCNPs) with a hexagonal phase are synthesized to optimize the doping contents of Yb3+ and to mitigate Yb-assocd. concn. quenching. Such UCNPs' emission contains an almost 3-fold enhanced peak around 540-570 nm, matching the excitation spectrum of a commonly used inhibitory opsin protein, halorhodopsin. The enhanced UCNPs are used as optical transducers to develop a fully implantable upconversion-based device for in vivo tetherless optogenetic inhibition, which is actuated by near-IR (NIR) light irradn. without any electronics. When the device is implanted into targeted sites deep in the rat brain, the elec. activity of the neurons is reliably inhibited with NIR irradn. and restores to normal level upon switching off the NIR light. The system is further used to perform tetherless unilateral inhibition of the secondary motor cortex in behaving mice, achieving control of their motor functions. This study provides an important and useful supplement to the upconversion-based optogenetic toolset, which is beneficial for both basic and translational neuroscience studies.
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178Yu, N.; Huang, L.; Zhou, Y.; Xue, T.; Chen, Z.; Han, G. Near-Infrared-Light Activatable Nanoparticles for Deep-Tissue-Penetrating Wireless Optogenetics. Adv. Healthc. Mater. 2019, 8 (6), 1801132, DOI: 10.1002/adhm.201801132There is no corresponding record for this reference.
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179Chen, S.; Weitemier, A. Z.; Zeng, X.; He, L.; Wang, X.; Tao, Y.; Huang, A. J. Y.; Hashimotodani, Y.; Kano, M.; Iwasaki, H. Near-Infrared Deep Brain Stimulation via Upconversion Nanoparticle-Mediated Optogenetics. Science 2018, 359 (6376), 679– 684, DOI: 10.1126/science.aaq1144179https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXit1CjtLk%253D&md5=c2f1bffdd2bff528c7df816fd9811a1eNear-infrared deep brain stimulation via upconversion nanoparticle-mediated optogeneticsChen, Shuo; Weitemier, Adam Z.; Zeng, Xiao; He, Linmeng; Wang, Xiyu; Tao, Yanqiu; Huang, Arthur J. Y.; Hashimotodani, Yuki; Kano, Masanobu; Iwasaki, Hirohide; Parajuli, Laxmi Kumar; Okabe, Shigeo; Teh, Daniel B. Loong; All, Angelo H.; Tsutsui-Kimura, Iku; Tanaka, Kenji F.; Liu, Xiaogang; McHugh, Thomas J.Science (Washington, DC, United States) (2018), 359 (6376), 679-684CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Optogenetics has revolutionized the exptl. interrogation of neural circuits and holds promise for the treatment of neurol. disorders. It is limited, however, because visible light cannot penetrate deep inside brain tissue. Upconversion nanoparticles (UCNPs) absorb tissue-penetrating near-IR (NIR) light and emit wavelength-specific visible light. Here, we demonstrate that molecularly tailored UCNPs can serve as optogenetic actuators of transcranial NIR light to stimulate deep brain neurons. Transcranial NIR UCNP-mediated optogenetics evoked dopamine release from genetically tagged neurons in the ventral tegmental area, induced brain oscillations through activation of inhibitory neurons in the medial septum, silenced seizure by inhibition of hippocampal excitatory cells, and triggered memory recall. UCNP technol. will enable less-invasive optical neuronal activity manipulation with the potential for remote therapy.
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180All, A. H.; Zeng, X.; Teh, D. B. L.; Yi, Z.; Prasad, A.; Ishizuka, T.; Thakor, N.; Hiromu, Y.; Liu, X. Expanding the Toolbox of Upconversion Nanoparticles for In Vivo Optogenetics and Neuromodulation. Adv. Mater. 2019, 31 (41), 1803474, DOI: 10.1002/adma.201803474180https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhs1aitr3F&md5=97761b5e5e7c660e387f7e823607df58Expanding the Toolbox of Upconversion Nanoparticles for In Vivo Optogenetics and NeuromodulationAll, Angelo Homayoun; Zeng, Xiao; Teh, Daniel Boon Loong; Yi, Zhigao; Prasad, Ankshita; Ishizuka, Toru; Thakor, Nitish; Hiromu, Yawo; Liu, XiaogangAdvanced Materials (Weinheim, Germany) (2019), 31 (41), 1803474CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Optogenetics is an optical technique that exploits visible light for selective neuromodulation with spatio-temporal precision. Despite enormous effort, the effective stimulation of targeted neurons, which are located in deeper structures of the nervous system, by visible light, remains a tech. challenge. Compared to visible light, near-IR illumination offers a higher depth of tissue penetration owing to a lower degree of light attenuation. Herein, an overview of advances in developing new modalities for neural circuitry modulation utilizing upconversion-nanoparticle-mediated optogenetics is presented. These developments have led to minimally invasive optical stimulation and inhibition of neurons with substantially improved selectivity, sensitivity, and spatial resoln. The focus is to provide a comprehensive review of the mechanistic basis for evaluating upconversion parameters, which will be useful in designing, executing, and reporting optogenetic expts.
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181Shao, B.; Yang, Z.; Wang, Y.; Li, J.; Yang, J.; Qiu, J.; Song, Z. Coupling of Ag Nanoparticle with Inverse Opal Photonic Crystals as a Novel Strategy for Upconversion Emission Enhancement of NaYF4: Yb3+, Er3+ Nanoparticles. ACS Appl. Mater. Interfaces 2015, 7 (45), 25211– 25218, DOI: 10.1021/acsami.5b06817181https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhslSlsbnL&md5=1d2d9a8f3573618e344bc6d839f11c2bCoupling of Ag Nanoparticle with Inverse Opal Photonic Crystals as a Novel Strategy for Upconversion Emission Enhancement of NaYF4:Yb3+,Er3+ NanoparticlesShao, Bo; Yang, Zhengwen; Wang, Yida; Li, Jun; Yang, Jianzhi; Qiu, Jianbei; Song, ZhiguoACS Applied Materials & Interfaces (2015), 7 (45), 25211-25218CODEN: AAMICK; ISSN:1944-8244. (American Chemical Society)Rare-earth-ion-doped upconversion (UC) nanoparticles have generated considerable interest because of their potential application in solar cells, biol. labeling, therapeutics, and imaging. However, the applications of UC nanoparticles were still limited because of their low emission efficiency. Photonic crystals and noble metal nanoparticles are applied extensively to enhance the UC emission of rare earth ions. A novel substrate consisting of inverse opal photonic crystals and Ag nanoparticles was prepd. by the template-assisted method, which was used to enhance the UC emission of NaYF4: Yb3+, Er3+ nanoparticles. The red or green UC emissions of NaYF4: Yb3+, Er3+ nanoparticles were selectively enhanced on the inverse opal substrates because of the Bragg reflection of the photonic band gap. Addnl., the UC emission enhancement of NaYF4: Yb3+, Er3+ nanoparticles induced by the coupling of metal nanoparticle plasmons and photonic crystal effects was realized on the Ag nanoparticles included in the inverse opal substrate. Coupling of Ag nanoparticle with inverse opal photonic crystals provides a useful strategy to enhance UC emission of rare-earth-ion-doped nanoparticles.
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182Chu, C.-Y.; Wu, P.-W.; Chen, J.-C.; Tsou, N.-T.; Lin, Y.-Y.; Lo, Y.-C.; Li, S.-J.; Chang, C.-W.; Chen, B.-W.; Tsai, C.-L. Flexible Optogenetic Transducer Device for Remote Neuron Modulation Using Highly Upconversion Efficient Dendrite-like Gold Inverse Opaline Structure. Adv. Healthc. Mater. 2022, 2101310, DOI: 10.1002/adhm.202101310There is no corresponding record for this reference.
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183Ahn, H.; Kim, S.; Kim, Y.; Kim, S.; Choi, J.; Kim, K. Plasmonic Sensing, Imaging, and Stimulation Techniques for Neuron Studies. Biosens. Bioelectron. 2021, 182, 113150, DOI: 10.1016/j.bios.2021.113150183https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXns1ehtLg%253D&md5=e2e2351e57925c82d84ed839267b7817Plasmonic sensing, imaging, and stimulation techniques for neuron studiesAhn, Heesang; Kim, Soojung; Kim, Yoonhee; Kim, Seungchul; Choi, Jong-ryul; Kim, KyujungBiosensors & Bioelectronics (2021), 182 (), 113150CODEN: BBIOE4; ISSN:0956-5663. (Elsevier B.V.)Studies to understand the structure, functions, and electrophysiol. properties of neurons have been conducted at the frontmost end of neuroscience. Such studies have led to the active development of high-performance research tools for exploring the neurobiol. at the cellular and mol. level. Following this trend, research and application of plasmonics, which is a technol. employed in high-sensitivity optical biosensors and high-resoln. imaging, is essential for studying neurons, as plasmonic nanoprobes can be used to stimulate specific areas of cells. In this study, three plasmonic modalities were explored as tools to study neurons and their responses: (1) plasmonic sensing of neuronal activities and neuron-related chems.; (2) performance-improved optical imaging of neurons using plasmonic enhancements; and (3) plasmonic neuromodulations. Through a detailed investigation of these plasmonic modalities and research subjects that can be combined with them, it was confirmed that plasmonic sensing, imaging, and stimulation techniques have the potential to be effectively employed for the study of neurons and understanding their specific mol. activities.
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184Bruno, G.; Melle, G.; Barbaglia, A.; Iachetta, G.; Melikov, R.; Perrone, M.; Dipalo, M.; De Angelis, F. All-Optical and Label-Free Stimulation of Action Potentials in Neurons and Cardiomyocytes by Plasmonic Porous Metamaterials. Adv. Sci. 2021, 8 (21), 2100627, DOI: 10.1002/advs.202100627184https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB38XjtVSru7c%253D&md5=417a8d4e2b497c33a936e854a7bdfddfAll-Optical and Label-Free Stimulation of Action Potentials in Neurons and Cardiomyocytes by Plasmonic Porous MetamaterialsBruno, Giulia; Melle, Giovanni; Barbaglia, Andrea; Iachetta, Giuseppina; Melikov, Rustamzhon; Perrone, Michela; Dipalo, Michele; De Angelis, FrancescoAdvanced Science (Weinheim, Germany) (2021), 8 (21), 2100627CODEN: ASDCCF; ISSN:2198-3844. (Wiley-VCH Verlag GmbH & Co. KGaA)Optical stimulation technologies are gaining great consideration in cardiol., neuroscience studies, and drug discovery pathways by providing control over cell activity with high spatio-temporal resoln. However, this high precision requires manipulation of biol. processes at genetic level concealing its development from broad scale application. Therefore, translating these technologies into tools for medical or pharmacol. applications remains a challenge. Here, an all-optical nongenetic method for the modulation of electrogenic cells is introduced. It is demonstrated that plasmonic metamaterials can be used to elicit action potentials by converting near IR laser pulses into stimulatory currents. The suggested approach allows for the stimulation of cardiomyocytes and neurons directly on com. complementary metal-oxide semiconductor microelectrode arrays coupled with ultrafast pulsed laser, providing both stimulation and network-level recordings on the same device.
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185Parameswaran, R.; Koehler, K.; Rotenberg, M. Y.; Burke, M. J.; Kim, J.; Jeong, K. Y.; Hissa, B.; Paul, M. D.; Moreno, K.; Sarma, N.; Hayes, T.; Sudzilovsky, E.; Park, H. G.; Tian, B. Optical Stimulation of Cardiac Cells with a Polymer-Supported Silicon Nanowire Matrix. Proc. Natl. Acad. Sci. U. S. A. 2019, 116 (2), 413– 421, DOI: 10.1073/pnas.1816428115185https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXlvVKltw%253D%253D&md5=2ecb717871943c39819259edfc89f675Optical stimulation of cardiac cells with a polymer-supported silicon nanowire matrixParameswaran, Ramya; Koehler, Kelliann; Rotenberg, Menahem Y.; Burke, Michael J.; Kim, Jungkil; Jeong, Kwang-Yong; Hissa, Barbara; Paul, Michael D.; Moreno, Kiela; Sarma, Nivedina; Hayes, Thomas; Sudzilovsky, Edward; Park, Hong-Gyu; Tian, BozhiProceedings of the National Academy of Sciences of the United States of America (2019), 116 (2), 413-421CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Electronic pacemakers can treat elec. conduction disorders in hearts; however, they are invasive, bulky, and linked to increased incidence of infection at the tissue-device interface. Thus, researchers have looked to other more biocompatible methods for cardiac pacing or resynchronization, such as femtosecond IR light pulsing, optogenetics, and polymer-based cardiac patches integrated with metal electrodes. Here the authors develop a biocompatible nongenetic approach for the optical modulation of cardiac cells and tissues. A polymer-silicon nanowire composite mesh can be used to convert fast moving, low-radiance optical inputs into stimulatory signals in target cardiac cells. The authors' method allows for the stimulation of the cultured cardiomyocytes or ex vivo heart to beat at a higher target frequency.
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186Jiang, Y.; Li, X.; Liu, B.; Yi, J.; Fang, Y.; Shi, F.; Gao, X.; Sudzilovsky, E.; Parameswaran, R.; Koehler, K.; Nair, V.; Yue, J.; Guo, K. H.; Fang, Y.; Tsai, H. M.; Freyermuth, G.; Wong, R. C. S.; Kao, C. M.; Chen, C. T.; Nicholls, A. W.; Wu, X.; Shepherd, G. M. G.; Tian, B. Rational Design of Silicon Structures for Optically Controlled Multiscale Biointerfaces. Nat. Biomed. Eng. 2018, 2 (7), 508– 521, DOI: 10.1038/s41551-018-0230-1186https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXhtFensrzO&md5=f13d567e5edd81f3e42c2d75ec1af79cRational design of silicon structures for optically controlled multiscale biointerfacesJiang, Yuanwen; Li, Xiaojian; Liu, Bing; Yi, Jaeseok; Fang, Yin; Shi, Fengyuan; Gao, Xiang; Sudzilovsky, Edward; Parameswaran, Ramya; Koehler, Kelliann; Nair, Vishnu; Yue, Jiping; Guo, KuangHua; Tsai, Hsiu-Ming; Freyermuth, George; Wong, Raymond C. S.; Kao, Chien-Min; Chen, Chin-Tu; Nicholls, Alan W.; Wu, Xiaoyang; Shepherd, Gordon M. G.; Tian, BozhiNature Biomedical Engineering (2018), 2 (7), 508-521CODEN: NBEAB3; ISSN:2157-846X. (Nature Research)Silicon-based materials have been widely used in biol. applications. However, remotely controlled and interconnect-free silicon configurations have been rarely explored, because of limited fundamental understanding of the complex physicochem. processes that occur at interfaces between silicon and biol. materials. Here, we describe rational design principles, guided by biol., for establishing intracellular, intercellular and extracellular silicon-based interfaces, where the silicon and the biol. targets have matched properties. We focused on light-induced processes at these interfaces, and developed a set of matrixes to quantify and differentiate the capacitive, Faradaic and thermal outputs from about 30 different silicon materials in saline. We show that these interfaces are useful for the light-controlled non-genetic modulation of intracellular calcium dynamics, of cytoskeletal structures and transport, of cellular excitability, of neurotransmitter release from brain slices and of brain activity in vivo.
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187Dogru-Yuksel, I. B.; Han, M.; Pirnat, G.; Magden, E. S.; Senses, E.; Humar, M.; Nizamoglu, S. High-Q, Directional and Self-Assembled Random Laser Emission Using Spatially Localized Feedback via Cracks. APL Photonics 2020, 5 (10), 106105, DOI: 10.1063/5.0020528187https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXotFWgt7c%253D&md5=857fc45bcfd3170607012509e4007b76High-Q, directional and self-assembled random laser emission using spatially localized feedback via cracksDogru-Yuksel, Itir Bakis; Han, Mertcan; Pirnat, Gregor; Magden, Emir Salih; Senses, Erkan; Humar, Matjaz; Nizamoglu, SedatAPL Photonics (2020), 5 (10), 106105CODEN: APPHD2; ISSN:2378-0967. (American Institute of Physics)Lasers based on Fabry-Perot or whispering gallery resonators generally require complex fabrication stages and sensitive alignment of cavity configurations. The structural defects on reflective surfaces result in scattering and induce optical losses that can be detrimental to laser performance. On the other hand, random lasers can be simply obtained by forming disordered gain media and scatterers, but they generally show omnidirectional emission with a low Q-factor. Here, we demonstrate directional random lasers with a high Q-factor emission (∼1.5 x 104) via self-assembled microstructural cracks that are spontaneously formed upon radial strain-release of colloidal nanoparticles from the wet to dry phase. The rough sidewalls of cracks facilitate light oscillation via diffuse reflection that forms a spatially localized feedback, and they also serve as the laser out-coupler. These self-assembled cracks exhibit random lasing at optical pump powers as low as tens of μJ/mm2. We demonstrate a wide variety of random lasers from nano- and biomaterials including silica nanoparticles, fluorescent proteins, and biopolymers. These findings pave the way toward self-assembled, configurable, and scalable random lasers for sensing, displays, and communication applications. (c) 2020 American Institute of Physics.
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188Wang, L.; Zhao, W.; Tan, W. Bioconjugated Silica Nanoparticles: Development and Applications. Nano Res. 2008, 1 (2), 99– 115, DOI: 10.1007/s12274-008-8018-3188https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtVymtLzL&md5=86ea65f84ba4dfe98d78b20b2ab5b225Bioconjugated silica nanoparticles: development and applicationsWang, Lin; Zhao, Wenjun; Tan, WeihongNano Research (2008), 1 (2), 99-115CODEN: NRAEB5; ISSN:1998-0124. (Springer)A review. Advanced bioanal., including accurate quantitation, has driven the need to understand biol. and medicine at the mol. level. Bioconjugated silica nanoparticles have the potential to address this emerging challenge. Particularly intriguing diagnostic and therapeutic applications in cancer and infectious disease as well as uses in gene and drug delivery, have also been found for silica nanoparticles. In this review, we describe the synthesis, bioconjugation, and applications of silica nanoparticles in different bioanal. formats, such as selective tagging, barcoding, and sepn. of a wide range of biomedically important targets. Overall, we envisage that further development of these nanoparticles will provide a variety of advanced tools for mol. biol., genomics, proteomics and medicine.
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189Petty, A. J.; Keate, R. L.; Jiang, B.; Ameer, G. A.; Rivnay, J. Conducting Polymers for Tissue Regeneration in Vivo †. Chem. Mater. 2020, 32 (10), 4095– 4115, DOI: 10.1021/acs.chemmater.0c00767189https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXnslaqsb0%253D&md5=adc651b2e64de8794e36a1455bab294fConducting Polymers for Tissue Regeneration in VivoPetty, Anthony J.; Keate, Rebecca L.; Jiang, Bin; Ameer, Guillermo A.; Rivnay, JonathanChemistry of Materials (2020), 32 (10), 4095-4115CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)A review. Conducting polymers (CPs) have unique electroactive properties that have inspired significant investigation into their use as biomaterials (CP-BMs) for regenerative engineering. Their phys. and optoelectronic properties, including bulk mixed electronic/ionic conduction, enable the fabrication of a multifunctional biomaterial that passively affects cellular response and modulates elec. field, charge injection, or drug delivery, allowing these materials to actively affect tissue regeneration processes. While material and device dependent cellular responses have been obsd. in vitro, fewer studies have attempted to translate these types of materials and methods to in vivo models. In this Perspective, we assess the CP-BM literature for nerve, spinal cord, bone, and skin regeneration applications with a comprehensive look at in vivo studies, which present an informative illustration of current progress and the state of the field.
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190Rivnay, J.; Wang, H.; Fenno, L.; Deisseroth, K.; Malliaras, G. G. Next-Generation Probes, Particles, and Proteins for Neural Interfacing. Sci. Adv. 2017, 3 (6), e1601649 DOI: 10.1126/sciadv.1601649190https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXmvFOmur4%253D&md5=212e6cb56c64fcba6110beb95f50680eNext-generation probes, particles, and proteins for neural interfacingRivnay, Jonathan; Wang, Huiliang; Fenno, Lief; Deisseroth, Karl; Malliaras, George G.Science Advances (2017), 3 (6), e1601649/1-e1601649/21CODEN: SACDAF; ISSN:2375-2548. (American Association for the Advancement of Science)Bidirectional interfacing with the nervous system enables neuroscience research, diagnosis, and therapy. This two-way communication allows us to monitor the state of the brain and its composite networks and cells as well as to influence them to treat disease or repair/restore sensory or motor function. To provide the most stable and effective interface, the tools of the trade must bridge the soft, ion-rich, and evolving nature of neural tissue with the largely rigid, static realm of microelectronics and medical instruments that allow for readout, anal., and/or control. In this Review, we describe how the understanding of neural signaling and material-tissue interactions has fueled the expansion of the available tool set. New probe architectures and materials, nanoparticles, dyes, and designer genetically encoded proteins push the limits of recording and stimulation lifetime, localization, and specificity, blurring the boundary between living tissue and engineered tools. Understanding these approaches, their modality, and the role of cross-disciplinary development will support new neurotherapies and prostheses and provide neuroscientists and neurologists with unprecedented access to the brain.
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191Kotov, N. A.; Winter, J. O.; Clements, I. P.; Jan, E.; Timko, B. P.; Campidelli, S.; Pathak, S.; Mazzatenta, A.; Lieber, C. M.; Prato, M.; Bellamkonda, R. V.; Silva, G. A.; Kam, N. W. S.; Patolsky, F.; Ballerini, L. Nanomaterials for Neural Interfaces. Adv. Mater. 2009, 21 (40), 3970– 4004, DOI: 10.1002/adma.200801984191https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXht12hurrJ&md5=4faa19e4dcf876f7b46b6d5021bbac33Nanomaterials for Neural InterfacesKotov, Nicholas A.; Winter, Jessica O.; Clements, Isaac P.; Jan, Edward; Timko, Brian P.; Campidelli, Stephane; Pathak, Smita; Mazzatenta, Andrea; Lieber, Charles M.; Prato, Maurizio; Bellamkonda, Ravi V.; Silva, Gabriel A.; Kam, Nadine Wong Shi; Patolsky, Fernando; Ballerini, LauraAdvanced Materials (Weinheim, Germany) (2009), 21 (40), 3970-4004CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)This review focuses on the application of nanomaterials for neural interfacing. The junction between nanotechnol. and neural tissues can be particularly worthy of scientific attention for several reasons: (i) Neural cells are electroactive, and the electronic properties of nanostructures can be tailored to match the charge transport requirements of elec. cellular interfacing. (ii) The unique mech. and chem. properties of nanomaterials are crit. for integration with neural tissue as long-term implants. (iii) Solns. to many crit. problems in neural biol./medicine are limited by the availability of specialized materials. (iv) Neuronal stimulation is needed for a variety of common and severe health problems. This confluence of need, accumulated expertise, and potential impact on the well-being of people suggests the potential of nanomaterials to revolutionize the field of neural interfacing. In this review, we begin with foundational topics, such as the current status of neural electrode (NE) technol., the key challenges facing the practical utilization of NEs, and the potential advantages of nanostructures as components of chronic implants. After that the detailed account of toxicol. and biocompatibility of nanomaterials in respect to neural tissues is given. Next, we cover a variety of specific applications of nanoengineered devices, including drug delivery, imaging, topog. patterning, electrode design, nanoscale transistors for high-resoln. neural interfacing, and photoactivated interfaces. We also critically evaluate the specific properties of particular nanomaterials-including nanoparticles, nanowires, and carbon nanotubes-that can be taken advantage of in neuroprosthetic devices. The most promising future areas of research and practical device engineering are discussed as a conclusion to the review.
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192Fattahi, P.; Yang, G.; Kim, G.; Abidian, M. R. A Review of Organic and Inorganic Biomaterials for Neural Interfaces. Adv. Mater. 2014, 26 (12), 1846– 1885, DOI: 10.1002/adma.201304496192https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXjtVKhsrg%253D&md5=acdcb2ebe1cb6f81a46c146a15ac693dA Review of Organic and Inorganic Biomaterials for Neural InterfacesFattahi, Pouria; Yang, Guang; Kim, Gloria; Abidian, Mohammad RezaAdvanced Materials (Weinheim, Germany) (2014), 26 (12), 1846-1885CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)A review. Recent advances in nanotechnol. have generated wide interest in applying nanomaterials for neural prostheses. An ideal neural interface should create seamless integration into the nervous system and performs reliably for long periods of time. As a result, many nanoscale materials not originally developed for neural interfaces become attractive candidates to detect neural signals and stimulate neurons. In this comprehensive review, an overview of state-of-the-art microelectrode technologies provided first, with focus on the material properties of these microdevices. The advancements in electro-active nanomaterials are then reviewed, including conducting polymers, carbon nanotubes, graphene, silicon nanowires, and hybrid org.-inorg. nanomaterials, for neural recording, stimulation, and growth. Finally, tech. and scientific challenges are discussed regarding biocompatibility, mech. mismatch, and elec. properties faced by these nanomaterials for the development of long-lasting functional neural interfaces.
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193Wang, M.; Mi, G.; Shi, D.; Bassous, N.; Hickey, D.; Webster, T. J. Nanotechnology and Nanomaterials for Improving Neural Interfaces. Adv. Funct. Mater. 2018, 28 (12), 1700905, DOI: 10.1002/adfm.201700905There is no corresponding record for this reference.
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194Qu, A.; Sun, M.; Kim, J. Y.; Xu, L.; Hao, C.; Ma, W.; Wu, X.; Liu, X.; Kuang, H.; Kotov, N. A.; Xu, C. Stimulation of Neural Stem Cell Differentiation by Circularly Polarized Light Transduced by Chiral Nanoassemblies. Nat. Biomed. Eng. 2021, 5 (1), 103– 113, DOI: 10.1038/s41551-020-00634-4194https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3cXitFKlu73J&md5=effe16bd472e2b236252239ba72d2a97Stimulation of neural stem cell differentiation by circularly polarized light transduced by chiral nanoassembliesQu, Aihua; Sun, Maozhong; Kim, Ji-Young; Xu, Liguang; Hao, Changlong; Ma, Wei; Wu, Xiaoling; Liu, Xiaogang; Kuang, Hua; Kotov, Nicholas A.; Xu, ChuanlaiNature Biomedical Engineering (2021), 5 (1), 103-113CODEN: NBEAB3; ISSN:2157-846X. (Nature Research)Abstr.: The biol. effects of circularly polarized light on living cells are considered to be negligibly weak. Here, we show that the differentiation of neural stem cells into neurons can be accelerated by circularly polarized photons when DNA-bridged chiral assemblies of gold nanoparticles are entangled with the cells cytoskeletal fibers. By using cell-culture expts. and plasmonic-force calcns., we demonstrate that the nanoparticle assemblies exert a circularly-polarized-light-dependent force on the cytoskeleton, and that the light-induced periodic mech. deformation of actin nanofibres with a frequency of 50 Hz stimulates the differentiation of neural stem cells into the neuronal phenotype. When implanted in the hippocampus of a mouse model of Alzheimers disease, neural stem cells illuminated following a polarity-optimized protocol reduced the formation of amyloid plaques by more than 70%. Our findings suggest that circularly polarized light can guide cellular development for biomedical use.
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195Kim, T.; McCall, J. G.; Jung, Y. H.; Huang, X.; Siuda, E. R.; Li, Y.; Song, J.; Song, Y. M.; Pao, H. A.; Kim, R.-H. Injectable, Cellular-Scale Optoelectronics with Applications for Wireless Optogenetics. Science (80-.). 2013, 340 (6129), 211– 216, DOI: 10.1126/science.1232437There is no corresponding record for this reference.
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196Park, K.; Deutsch, Z.; Li, J. J.; Oron, D.; Weiss, S. Single Molecule Quantum-Confined Stark Effect Measurements of Semiconductor Nanoparticles at Room Temperature. ACS Nano 2012, 6 (11), 10013– 10023, DOI: 10.1021/nn303719m196https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhsFektb3I&md5=5d4a44c41119439686410b5d8ceab834Single Molecule Quantum-Confined Stark Effect Measurements of Semiconductor Nanoparticles at Room TemperaturePark, KyoungWon; Deutsch, Zvicka; Li, J. Jack; Oron, Dan; Weiss, ShimonACS Nano (2012), 6 (11), 10013-10023CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)The authors measured the quantum-confined Stark effect (QCSE) of several types of fluorescent colloidal semiconductor quantum dots and nanorods at the single mol. level at room temp. These measurements demonstrate the possible utility of these nanoparticles for local elec. field (voltage) sensing on the nanoscale. Charge sepn. across one (or more) heterostructure interface(s) with type-II band alignment (and the assocd. induced dipole) is crucial for an enhanced QCSE. To further gain insight into the exptl. results, the authors numerically solved the Schroedinger and Poisson equations under SCF approxn., including dielec. inhomogeneities. Both calcns. and probably the degree of initial charge sepn. (and the assocd. exciton binding energy) dets. the magnitude of the QCSE in these structures.
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197Marshall, J. D.; Schnitzer, M. J. Optical Strategies for Sensing Neuronal Voltage Using Quantum Dots and Other Semiconductor Nanocrystals. ACS Nano 2013, 7 (5), 4601– 4609, DOI: 10.1021/nn401410k197https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmtleluro%253D&md5=ef3473b82f43a25f9e500937d82a89f9Optical Strategies for Sensing Neuronal Voltage Using Quantum Dots and Other Semiconductor NanocrystalsMarshall, Jesse D.; Schnitzer, Mark J.ACS Nano (2013), 7 (5), 4601-4609CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)Biophysicists have long sought optical methods capable of reporting the electrophysiol. dynamics of large-scale neural networks with millisecond-scale temporal resoln. Existing fluorescent sensors of cell membrane voltage can report action potentials in individual cultured neurons, but limitations in brightness and dynamic range of both synthetic org. and genetically encoded voltage sensors have prevented concurrent monitoring of spiking activity across large populations of individual neurons. Here we propose a novel, inorg. class of fluorescent voltage sensors: semiconductor nanoparticles, such as ultrabright quantum dots (qdots). Our calcns. revealed that transmembrane elec. fields characteristic of neuronal spiking (∼10 mV/nm) modulate a qdot's electronic structure and can induce ∼5% changes in its fluorescence intensity and ∼1 nm shifts in its emission wavelength, depending on the qdot's size, compn., and dielec. environment. Moreover, tailored qdot sensors composed of two different materials can exhibit substantial (∼30%) changes in fluorescence intensity during neuronal spiking. Using signal detection theory, we show that conventional qdots should be capable of reporting voltage dynamics with millisecond precision across several tens or more individual neurons over a range of optical and neurophysiol. conditions. These results unveil promising avenues for imaging spiking dynamics in neural networks and merit in-depth exptl. investigation.
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198Park, K.; Weiss, S. Design Rules for Membrane-Embedded Voltage-Sensing Nanoparticles. Biophys. J. 2017, 112 (4), 703– 713, DOI: 10.1016/j.bpj.2016.12.047198https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1Wnu74%253D&md5=92b969abd0b67af96a78a338ec25af05Design Rules for Membrane-Embedded Voltage-Sensing NanoparticlesPark, Kyoungwon; Weiss, ShimonBiophysical Journal (2017), 112 (4), 703-713CODEN: BIOJAU; ISSN:0006-3495. (Cell Press)Voltage-sensing dyes and voltage-sensing fluorescence proteins have been continually improved and as a result provided a wealth of insights into neuronal circuits. Further improvements in voltage-sensing dyes and voltage-sensing fluorescence proteins are needed, however, for routine detection of single action potentials across a large no. of individual neurons in a large field-of-view of a live mammalian brain. However, recent expts. and calcns. suggest that semiconducting nanoparticles could act as efficient voltage sensors, suitable for the above-mentioned task. This study presents quantum mech. calcns., including Auger recombination rates, of the quantum-confined Stark effect in membrane-embedded semiconducting nanoparticles, examines their possible utility as membrane voltage sensors, and provide design rules for their structure and compn.
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199Caglar, M.; Pandya, R.; Xiao, J.; Foster, S. K.; Divitini, G.; Chen, R. Y. S.; Greenham, N. C.; Franze, K.; Rao, A.; Keyser, U. F. All-Optical Detection of Neuronal Membrane Depolarization in Live Cells Using Colloidal Quantum Dots. Nano Lett. 2019, 19, 8539– 8549, DOI: 10.1021/acs.nanolett.9b03026199https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1MXitVymsrbK&md5=29d0c77990084234e30ebf109e665260All-Optical Detection of Neuronal Membrane Depolarization in Live Cells Using Colloidal Quantum DotsCaglar, Mustafa; Pandya, Raj; Xiao, James; Foster, Sarah K.; Divitini, Giorgio; Chen, Richard Y. S.; Greenham, Neil C.; Franze, Kristian; Rao, Akshay; Keyser, Ulrich F.Nano Letters (2019), 19 (12), 8539-8549CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Luminescent semiconductor quantum dots (QDs) have recently been suggested as novel probes for imaging and sensing cell membrane voltages. However, a key bottleneck for their development is a lack of techniques to assess QD responses to voltages generated in the aq. electrolytic environments typical of biol. systems. Even more generally, there have been relatively few efforts to assess the response of QDs to voltage changes in live cells. Here, the authors develop a platform for monitoring the photoluminescence (PL) response of QDs under AC and DC voltage changes within aq. ionic environments. The authors evaluate both traditional CdSe/CdS and more biol. compatible InP/ZnS QDs at a range of ion concns. to establish their PL/voltage characteristics on chip. Wide-field, few-particle PL measurements with neuronal cells show the QDs can be used to track local voltage changes with greater sensitivity (ΔPL up to twice as large) than state-of-the-art calcium imaging dyes, making them particularly appealing for tracking sub-threshold events. Addnl. physiol. observation studies showed that while CdSe/CdS dots have greater PL responses on membrane depolarization, their lower cytotoxicity makes InP/ZnS far more suitable for voltage sensing in living systems. The results provide a methodol. for the rational development of QD voltage sensors and highlight their potential for imaging changes in cell membrane voltage.
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200Ghosh, S.; Chen, Y.; George, A.; Dutta, M.; Stroscio, M. A. Fluorescence Resonant Energy Transfer-Based Quantum Dot Sensor for the Detection of Calcium Ions. Front. Chem. 2020, 8, 1– 9, DOI: 10.3389/fchem.2020.00594There is no corresponding record for this reference.
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201Savchenko, A.; Cherkas, V.; Liu, C.; Braun, G. B.; Kleschevnikov, A.; Miller, Y. I.; Molokanova, E. Graphene Biointerfaces for Optical Stimulation of Cells. Sci. Adv. 2018, 4 (5), eaat0351 DOI: 10.1126/sciadv.aat0351There is no corresponding record for this reference.
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202Barbaglia, A.; Dipalo, M.; Melle, G.; Iachetta, G.; Deleye, L.; Hubarevich, A.; Toma, A.; Tantussi, F.; De Angelis, F. Mirroring Action Potentials: Label-Free, Accurate, and Noninvasive Electrophysiological Recordings of Human-Derived Cardiomyocytes. Adv. Mater. 2021, 33 (7), 2004234, DOI: 10.1002/adma.202004234202https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXosVSjsw%253D%253D&md5=eecb8e2c8fbc74e2b1b17aca8d4869e2Mirroring Action Potentials: Label-Free, Accurate, and Noninvasive Electrophysiological Recordings of Human-Derived CardiomyocytesBarbaglia, Andrea; Dipalo, Michele; Melle, Giovanni; Iachetta, Giuseppina; Deleye, Lieselot; Hubarevich, Aliaksandr; Toma, Andrea; Tantussi, Francesco; De Angelis, FrancescoAdvanced Materials (Weinheim, Germany) (2021), 33 (7), 2004234CODEN: ADVMEW; ISSN:0935-9648. (Wiley-VCH Verlag GmbH & Co. KGaA)The electrophysiol. recording of action potentials in human cells is a long-sought objective due to its pivotal importance in many disciplines. Among the developed techniques, invasiveness remains a common issue, causing cytotoxicity or altering unpredictably cell physiol. response. In this work, a new approach for recording intracellular signals of outstanding quality and with noninvasiveness is introduced. By taking profit of the concept of mirror charge in classical electrodynamics, the new proposed device transduces cell ionic currents into mirror charges in a microfluidic chamber, thus realizing a virtual mirror cell. By monitoring mirror charge dynamics, it is possible to effectively record the action potentials fired by the cells. Since there is no need for accessing or interacting with the cells, the method is intrinsically noninvasive. In addn., being based on optical recording, it shows high spatial resoln. and high parallelization. As shown through a set of expts., the presented methodol. is an ideal candidate for the next generation devices for the reliable assessment of cardiotoxicity on human-derived cardiomyocytes. More generally, it paves the way toward a new family of in vitro biodevices that will lay a new milestone in the field of electrophysiol.
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203Iachetta, G.; Colistra, N.; Melle, G.; Deleye, L.; Tantussi, F.; De Angelis, F.; Dipalo, M. Improving Reliability and Reducing Costs of Cardiotoxicity Assessments Using Laser-Induced Cell Poration on Microelectrode Arrays. Toxicol. Appl. Pharmacol. 2021, 418, 115480, DOI: 10.1016/j.taap.2021.115480203https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BB3MXnvFeqsrY%253D&md5=3323aacdcb3fdee9a570d1677f8322eeImproving reliability and reducing costs of cardiotoxicity assessments using laser-induced cell poration on microelectrode arraysIachetta, Giuseppina; Colistra, Nicolo; Melle, Giovanni; Deleye, Lieselot; Tantussi, Francesco; De Angelis, Francesco; Dipalo, MicheleToxicology and Applied Pharmacology (2021), 418 (), 115480CODEN: TXAPA9; ISSN:0041-008X. (Elsevier Inc.)Drug-induced cardiotoxicity is a major barrier to drug development and a main cause of withdrawal of marketed drugs. Drugs can strongly alter the spontaneous functioning of the heart by interacting with the cardiac membrane ion channels. If these effects only surface during in vivo preclin. tests, clin. trials or worse after commercialization, the societal and economic burden will be significant and seriously hinder the efficient drug development process. Hence, cardiac safety pharmacol. requires in vitro electrophysiol. screening assays of all drug candidates to predict cardiotoxic effects before clin. trials. In the past 10 years, microelectrode array (MEA) technol. began to be considered a valuable approach in pharmaceutical applications. However, an effective tool for high-throughput intracellular measurements, compatible with pharmaceutical stds., is not yet available. Here, we propose laser-induced optoacoustic poration combined with CMOS-MEA technol. as a reliable and effective platform to detect cardiotoxicity. This approach enables the acquisition of high-quality action potential recordings from large nos. of cardiomyocytes within the same culture well, providing reliable data using single-well MEA devices and single cardiac syncytia per each drug. Thus, this technol. could be applied in drug safety screening platforms reducing times and costs of cardiotoxicity assessments, while simultaneously improving the data reliability.
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