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Single-Cell Photothermal Neuromodulation for Functional Mapping of Neural Networks
摘要： Photothermal neuromodulation is one of the emerging technologies being developed for neuroscience studies because it can provide minimal-invasive control of neural activity in the deep brain with sub-millimeter precision. However, single cell modulation without genetic modification still remains a challenge, hindering its path to the broad application. Here, we introduce a nanoplasmonic approach to inhibit single neural activity with high temporal resolution. Low intensity of near infrared (NIR) was focused at single cell size on gold nanorod (GNR) integrated microelectrode array platform, generating photothermal effect underneath a target neuron for photothermal stimulation. We found that the photothermal stimulation modulates the spontaneous activity of a target neuron in an inhibitory manner. Single neuron inhibition was fast and highly reliable without thermal damage, and it can induce changes in network firing patterns, potentially suggesting their application for in vivo circuit modulation and functional connectomes.
关键词： photothermal effects,local surface plasmonic resonance,neuromodulation,gold nanorod,neuron
更新于2025-09-23 15:23:52
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Supramolecular Photothermal Nanomaterials as an Emerging Paradigm toward Precision Cancer Therapy
摘要： The concept of the “supramolecular photothermal effects” refers to the collection property and photothermal conversion efficiency resulting from the supramolecular assembly of molecular photothermal sensitizers. This review considers organic supramolecular photothermal materials assembled at the nanoscale via various molecular self-assembly strategies and associated with the organization of multiple noncovalent interactions. In these materials, the individual photosensitizer molecules are typically aggregated through self-assembly in a certain form that exhibits enhanced biostability, increased photothermal conversion efficiency with photoluminescence quenching, and improved photothermal therapeutic effects in comparison with those of the monomeric photosensitizer molecules. These supramolecular photothermal effects are controlled or influenced by intermolecular noncovalent interactions, especially the hydrophobic effects, which are distinct from the mechanisms of conventional sensitizer molecules and polymers and inorganic photothermal agents. A focus lies on how self-assembly strategies give rise to supramolecular photothermal effects, including polymer and protein fabrication, small molecule self-assembly, and the construction of donor–acceptor binary systems. Emphases are placed on the rational design of supramolecular photothermal nanomaterials, drug delivery, and in vivo photothermal therapeutic effects. Finally, the key challenges and promising prospects of these supramolecular photothermal nanomaterials in terms of both technical advances and clinical translation are discussed.
关键词： photothermal therapy,nanomaterials,cancer therapy,supramolecular photothermal effects,self-assembly
更新于2025-09-23 15:21:21
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Photothermal Effects Induced by Surface Plasmon Resonance at Graphene/Gold Nanointerfaces: A Multiscale Modeling Study
摘要： Surface plasmon resonance (SPR) biosensors have enormous potential in biological recognitions and biomolecular interactions, especially for the real time measurement of disease diagnosis and drug screening. Extensive efforts have been invested to ameliorate the sensing performances, while the photothermal effects, which are induced by the plasmon resonance, have an obvious impact. However, due to the limitations of experimental approaches, the theoretical mechanisms and specific influences of the SPR sensors with photothermal effects are few researched. Here, a multiscale simulation method is developed to investigate the photothermal effects at graphene/gold (Au) nanointerfaces, and to calculate the quantitative contribution of the photothermal effects towards high reliability SPR sensors in order to elucidate their influence on the sensing performances by means of first-principle calculations and molecular dynamics simulations. Our results indicate that the sensitivity and detection accuracy of graphene/Au SPR sensors can be tailored from 0 K to 600 K, due to the tunable dielectric constants of Au and graphene films through temperature variation. By controlling the its material thickness, interfacial combination and lattice strain, an optimized graphene/Au SPR sensor with higher sensitivity, detection accuracy, and reliability to the temperature rising has been achieved. Such multiscale simulation method, which is capable of seeking both the role and the underlying mechanism of the interfacial phenomena, can serve as an excellent guideline for the performance optimization and commercialized application of SPR sensors in the analytical chemistry and biomedical fields.
关键词： graphene/gold nanointerface,photothermal effects,surface plasmon resonance,multiscale simulation method,sensitivity and detection accuracy
更新于2025-09-23 15:21:21
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Impact of Plasmonic Photothermal Effects on the Reactivity of Au Nanoparticle Modified Graphene Electrodes Visualized Using Scanning Electrochemical Microscopy
摘要： Atomically-thin graphene electrodes enable the modulation of interfacial reactivity by means of underlying substrate effects. Here we show that plasmonic excitation of microscopic arrays composed of 50 nm Au nanoparticles situated underneath a graphene interface results in localized enhancements on the electrochemical readout. We used scanning electrochemical microscopy (SECM) in the feedback and H2O2 collection modes to identify the role of the generated plasmons on the electrochemical response. Using electrochemical imaging, supported by finite-element method simulations, we confirmed that a temperature rise of up to ~30 K was responsible for current enhancements observed for mass transfer-limited reactions. On single-layer graphene (SLG) we observed a shift in the onset of H2O2 generation which we traced back to photothermal induced kinetic changes, raising ko’ from 1.1 x 10-8 m/s to 2.2 x 10-7 m/s. Thicker 10-layer graphene electrodes displayed only a small kinetic difference with respect to SLG, suggesting that photothermal processes, in contrast to hot carriers, are the main contributor to the observed changes in interfacial reactivity upon illumination. SECM is demonstrated to be a powerful technique for elucidating thermal contributions to reactive enhancements, and presents a convenient platform for studying temperature-dependent phenomena over individual sites on electrodes.
关键词： scanning electrochemical microscopy,graphene electrodes,plasmonic photothermal effects,Au nanoparticle,electrochemical reactivity
更新于2025-09-19 17:13:59
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Long-Range Distributed Solar Irradiance Sensing Using Optical Fibers
摘要： Until recently, the amount of solar irradiance reaching the Earth surface was considered to be a steady value over the years. However, there is increasing observational evidence showing that this quantity undergoes substantial variations over time, which need to be addressed in different scenarios ranging from climate change to solar energy applications. With the growing interest in developing solar energy technology with enhanced efficiency and optimized management, the monitoring of solar irradiance at the ground level is now considered to be a fundamental input in the pursuit of that goal. Here, we propose the first fiber-based distributed sensor able of monitoring ground solar irradiance in real time, with meter scale spatial resolutions over distances of several tens of kilometers (up to 100 km). The technique is based on an optical fiber reflectometry technique (CP-φOTDR), which enables real time and long-range high-sensitivity bolometric measurements of solar radiance with a single optical fiber cable and a single interrogator unit. The method is explained and analyzed theoretically. A validation of the method is proposed using a solar simulator irradiating standard optical fibers, where we demonstrate the ability to detect and quantify solar irradiance with less than a 0.1 W/m2 resolution.
关键词： optical time domain reflectometry,photothermal effects,distributed sensing,rayleigh scattering,optical fiber sensors,solar irradiance,solar energy,optical radiation
更新于2025-09-19 17:13:59
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The effects of gold nanoparticles characteristics and laser irradiation conditions on spatiotemporal temperature pattern of an agar phantom: a simulation and MR thermometry study
摘要： In this paper, the effects of parameters related to gold nanoparticles (type, size, and concentration) and the laser parameters on spatiotemporal temperature pattern of an agar phantom during a photothermal therapy (PTT) procedure were modeled and then experimentally verified. Eight agar phantoms loaded by gold nanoparticles were made. An agar phantom without any nanoparticles was also considered as the control. Different sizes of two types of gold nanoparticles (spherical and silica-gold core shell) at various concentrations were studied. The phantoms were irradiated by various laser powers for 5 minutes. The temperature changes in each phantom was firstly calculated using COMSOL Multiphysics software. Also, each phantom was irradiated by laser and MR thermometry was performed to validate the simulation results. A reasonable correlation between simulation and MR thermometry was obtained (R=0.92). The error interval between calculations and experiments was ranged from ±3% to ±6%. It was clearly evident that laser irradiation conditions and nanoparticle characteristics affected the temperature rise profile. Spherical 20nm gold nanoparticles had better thermal efficiency and generated higher level of heat. The protocol suggested in this study may be appropriate to make a pre-clinical calculation and effect visualization for any nanoparticles-based PTT procedure before entrance into the clinics.
关键词： Nanotechnology,Cancer,Thermometry,Laser,Photothermal effects
更新于2025-09-12 10:27:22
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Tensile control of the thermal flow in plasmonic heaters realized on flexible substrates
摘要： In this paper, we present a simple and robust numerical method capable of predicting, with high accuracy, the thermal effects occurring for different gold nanoparticle arrangements under externally applied strain. The physical system is numerically implemented in the COMSOL Multiphysics simulation platform. The photothermal response of different arrangements of gold nanoparticles, resonantly excited by linearly polarized light, is considered with the system at rest and under the action of mechanical stress. The generation of heat at the nanoscale is analyzed by considering how this is affected by the variation of the extinction cross section. We describe the peculiar conditions under which mechanically controlled gold nanoparticle arrangements can significantly increase the local temperature due to the formation of localized photothermal hot spots. The resulting systems are envisioned in applications as optomechanically tunable plasmonic heaters.
关键词： COMSOL Multiphysics,photothermal effects,mechanical stress,plasmonic heaters,gold nanoparticles
更新于2025-09-12 10:27:22
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Photoactive Nanocarriers for Controlled Delivery
摘要： Photoactive nanocarriers have emerged as robust and minimally invasive systems for the on-demand delivery of active payloads. The easy manipulation offered by light irradiation as an external stimulus allows precise spatiotemporal control of payload release based on the time, intensity, location, and wavelength of light exposure. Compared to conventional passive delivery systems, photoactive nanocarriers offer the possibility of tailoring the release kinetics of the encapsulated active molecules, which is of considerable clinical relevance for targeted delivery to desired sites of interest. In this progress report, the recent advances in the design and fabrication of photoactive nanoplatforms based on three main modes of mechanisms: photochemical reactions, the photothermal effect, and photosensitization mechanism mediated by reactive oxygen species are highlighted. The combination of these mechanisms provides additional flexibility for the effective delivery of therapeutics and improved synergistic therapeutic effects. Finally, challenges in future perspectives on the development of photoactive nanomaterials and their medical translation are discussed.
关键词： photothermal effects,photosensitization,photochemical reaction,nanocarriers,controlled delivery
更新于2025-09-11 14:15:04
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Plasmon-Mediated Chemical Reactions on Nanostructures Unveiled by Surface-Enhanced Raman Spectroscopy
摘要： Surface plasmons (SPs) originating from the collective oscillation of conduction electrons in nanostructured metals (Au, Ag, Cu, etc.) can redistribute not only the electromagnetic fields but also the excited carriers (electrons and holes) and heat energy in time and space. Therefore, SPs can engage in a variety of processes, such as molecular spectroscopy and chemical reaction. Recently, plenty of demonstrations have made plasmon-mediated chemical reactions (PMCRs) a very active research field and make it as a promising approach to facilitate light-driven chemical reactions under mild conditions. Concurrently, making use of the same SPs, surface-enhanced Raman spectroscopy (SERS) with a high surface sensitivity and energy resolution becomes a powerful and commonly used technique for the in situ study of PMCRs.
关键词： Surface plasmons,Photothermal effects,Hot electrons,Hot holes,Surface-enhanced Raman spectroscopy,Plasmon-mediated chemical reactions
更新于2025-09-11 14:15:04
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Engineering Interface-Dependent Photoconductivity in Ge <sub/>2</sub> Sb <sub/>2</sub> Te <sub/>5</sub> Nanoscale Devices
摘要： Phase change materials are increasingly being explored for photonics applications, ranging from high resolution displays to artificial retinas. Surprisingly, our understanding of the underlying mechanism of light-matter interaction in these materials has been limited to photothermal crystallization, because of its relevance in applications such as re-writable optical discs. Here we report a photoconductivity study of nanoscale thin films of phase change materials. We identify strong photoconductive behaviour in phase change materials, which we show to be a complex interplay of three independent mechanisms: photoconductive, photo induced-crystallization and photo-induced-thermoelectric effects. We find these effects also congruously contribute to a substantial photovoltaic effect, even in notionally symmetric devices. Notably, we show that device engineering plays a decisive role in determining the dominant mechanism; the contribution of the photothermal effects to the extractable photocurrent can be reduced to < 0.4 % by varying the electrodes and device geometry. We then show that the contribution of these individual effects to the photoresponse is phase-dependent with the amorphous state being more photoactive than the crystalline state and that a reversible change occurs in the charge transport from thermionic to tunnelling during phase transformation. Finally we demonstrate photodetectors with an order of magnitude tuneability in photodetection responsivity and bandwidth using these materials. Our results provide insight to the photo-physics of phase change materials and highlight their potential in future opto-electronics.
关键词： Mixed-Mode Operation,Photothermal effects,Tuneable Photodetector,Phase Change Materials,Photoconductivity
更新于2025-09-10 09:29:36