Light Stimulation Research Articles

Supramolecular Spring-Like Fe(II) Spin-Crossover Complexes Experiencing Giant and Anisotropic Thermal Expansion Across Two Distinct Temperature Regimes.

Dynamic molecules with tunable chemical and physical properties in response to external stimuli hold great potential for applications in information storage, smart molecular machines, and biomimetics. Among them, supramolecular springs and spin-crossover (SCO) complexes can both undergo visible macroscopic changes under heat or light stimulation. In this study, we synthesized a trinuclear Fe(II)-SCO complex, [(R-L)FeII{Au(CN)2}2] (R1), using a chiral chelating ligand decorated with rotatable benzyl rings. The [FeAu2] trinuclear molecules form a 21-helical supramolecular chain via elastic Au∙∙∙Au contacts. Interestingly, the synergy between the multiple dynamic factors (SCO event, rotation of the rings, and flexibility in Au∙∙∙Au distance) endows the complex with multiple switchings in both magnetism and structure, as well as the most intriguing characteristic of giant and anisotropic "breathing" feature in thermal expansion within two distinct temperature regimes. Specifically, complex R1 undergoes two hysteretic magnetic transitions: a non-spin transition and an unsymmetric SCO transition. Both transitions are triggered/accompanied by the rotation of the benzyl rings. Correspondingly, reversible spring-like motions of the helical chains are observed in the two distinct temperature regimes. This work demonstrates a significant success in incorporating both SCO and spring-like motion in one system, paving the way for designing multifunctional dynamic materials for future devices.

CdSe quantum dots photoelectric memristors for simulating biological visual system behavior

The visual system is the most important in the biological neurosensory system, so simulation of the biological visual system is the key for developing artificial nervous system. This work incorporates a CdSe quantum dot layer into silk fibroin based memristor device, endowing the devices with light-responsive capability. Furthermore, interesting phenomena were observed when the device operated as artificial synapses: excessive voltage stimulation led to a reduction in synaptic weight compared to the responses observed under normal electrical stimulation. This behavior mirrors sensations associated with pain, neuroprotection, and potential injuries to the neural system. At the end, we designed a visual perception system, simulating processes of the biological light intensity perception and the visual degradation response under intense light stimulation. Our research demonstrates the feasibility of constructing an artificial visual nervous system using a hardware system based on memristors.

Optogenetics and Its Transformative Role in Tissue Engineering and Regenerative Medicine

ABSTRACTOptogenetics, a revolutionary technique leveraging light stimulation for precise cellular control, holds immense potential in regenerative medicine. Offering unparalleled spatial and temporal accuracy, the entrance of optogenetics into tissue engineering and regenerative medicine (TERM) empowers researchers to modify genes precisely and reversibly, control signal pathways and antibodies, as well as alter biomaterial properties. Optogenetics provides unprecedented control in the manipulation of physiological regeneration, replication of intricate developmental processes, and tissue engineering in a laboratory setting. Although further investigation is required for the safe and feasible injection of optogenetic systems into human bodies, the use of optogenetics has already led to a great amount of research on several tissues and systems. It has found diverse applications in TERM of skin and connective tissue, endothelium, bone, cartilage, and muscle; with researchers leveraging optogenetics for precise control over the in vitro or in vivo production of these tissues, the investigation of critical proteins and pathways, the creation of light‐controlled wound coverings and even as a tool for directional tissue growth in living subjects. Optogenetics emerges as a transformative force in shaping the future of medical science, demonstrating a pivotal role in advancing regenerative medicine and paving the way for innovative therapeutic strategies.

Photothermally‐Induced Reversible Rigidity of Nacre‐Mimetic Composites Toward Semi‐Active Personal Safeguard

AbstractThe capacity to withstand challenges posed by complex environments is crucial for developing advanced high‐performance protective materials with mechanically adjustable nature. By constructing long‐range hierarchical network of shear‐stiffening gel‐carbon nanotube‐cellulose nanofiber (SCC) embedded within epoxy resin (ER), this work engineers a nacre‐inspired variable‐stiffness SCC‐ER composite (SCCE). Lightweight SCC scaffold attenuates falling impact force from 2.23 to 0.46 kN, and reaches 60 °C within 20 s under 1 sun exposure. Additionally, owing to the rigid ER matrix, SCCE exhibits 4.03 GPa elastic modulus, outperforming numerous conventional engineering materials in puncture resistance. Specific energy absorption of nacre‐mimetic SCCE presents 1.91 MJ m−3 while that of random structural SCCE is only 0.50 MJ m−3. More importantly, SCCE features representative photothermal‐induced reversible rigidity whose storage modulus varies from 9.85 MPa at 30 °C to 11.61 kPa at 116 °C under light stimulation. It also presents shape‐programmability, capable of adhering complex structural surfaces for protection. Eventually, SCCE‐based semi‐active adjustable protectors are constructed that leverage contactless photothermal effect to modulate rigidity. 5 mm‐thick smart SCCE‐protectors resist 163.93 m s−1 ballistic impact while 15‐mm commercial kneepads are penetrated at lower speed of 136.98 m s−1. This bio‐inspired semi‐active strategy proposes a promising avenue for enhancing personal protective equipment.

Light induces a rapid increase in cAMP and activates PKA in rod outer segments of the frog retina.

The phototransduction cascade enables the photoreceptor to detect light over a wide range of intensities without saturation. The main second messenger of the cascade is cGMP and the primary regulatory mechanism is calcium feedback. However, some experimental data suggest that cAMP may also play a role in regulating the phototransduction cascade, but this would require changes in cAMP on a time scale of seconds. Currently, there is a lack of data on the dynamics of changes in intracellular cAMP levels on this timescale. This is largely due to the specificity of the sensory modality of photoreceptors, which makes it practically impossible to use conventional experimental approaches based on fluorescence methods. In this study, we employed the method of rapid cryofixation of retinal samples after light stimulation and subsequent isolation of outer segment preparations. The study employed highly sensitive metabolomics approaches to measure levels of cAMP. Additionally, PKA activity was measured in the samples using a western blot. The results indicate that when exposed to near-saturating but still moderate light, cAMP levels increase transiently within the first second and then return to pre-stimulus levels. The increase in cAMP activates PKA, resulting in the phosphorylation of PKA-specific substrates in frog retinal outer segments.

Construction and Performance Study of an Injectable Dual-Network Hydrogel Dressing with Inherent Drainage Function.

With the widespread utilization of moist wound dressings, the extended healing time and increased risk of wound infection caused by excessively moist environments have garnered significant attention. The development of hydrogel dressings that can effectively control the wound moisture level and promote healing is very important. Inspired by the pore-opening perspiration effect of the skin, this study constructed an injectable dual-network hydrogel, CMCS-OSA/AG/MXene, by the composition of a dynamic covalent network of carboxymethyl chitosan and oxidized sodium alginate based on the Schiff base and hydrogen bond network of the thermosensitive low-melting-point agar with the advantage of the upper critical solution temperature (UCST) effect. Under near-infrared (NIR) light stimulation, the CMCS-OSA/AG/MXene hydrogel shows characteristics conducive to rapid removal of wound exudate while maintaining an appropriate moist environment for the wound and excellent antibacterial effects with its photothermal responses. The excellent conductivity of the hydrogel can also promote cell proliferation under external electrical stimulation (ES). Further validation through animal experiments on a full-thickness skin defect model demonstrates the excellent capability of CMCS-OSA/AG/MXene in accelerating wound healing. This work provides an innovative approach to the development of injectable hydrogel dressing materials with inherent drainage functionality and shows a new avenue to wound moisture control and wound healing promotion.

Near-infrared light stimulation regulates neural oscillation and memory behavior of mice with Alzheimer's disease.

Photobiomodulation (PBM) is a non-invasive neuromodulation technique for the brain. Low-intensity near-infrared light (1-500 mw) has demonstrated the ability to improve memory in Alzheimer's disease (AD) model mice, suggesting its potential for AD treatment. However, the impact of PBM on neural oscillations in the hippocampal region affected by AD remains unknown. In this study, AD model mice were subjected to PBM for 60 days and then tested using novel object recognition behavior (NOR) experiments. During behavioral experiments, local field potential signals (LFP) of the mice was recorded using a single electrode in the CA1 region to analyze memory ability and neural oscillation characteristics. The results revealed that mice stimulated with PBM exhibited significantly higher new object differentiation indices compared to the Sham group (p < 0.01). Furthermore, PBM stimulation led to a significant increase in relative power and sample entropy of theta and gamma bands (p < 0.01). The coupling intensities of θ-low-γ and θ-high-γ were also significantly higher in the PBM group compared to the Sham group (p < 0.01). In conclusion, these findings suggest that PBM may improve memory ability in AD mice through regulation of neural oscillation characteristics, providing a theoretical basis for utilizing PBM as a treatment modality for Alzheimer's disease.

X-ray/γ-ray/Ultrasound-Activated Persistent Luminescence Phosphors for Deep Tissue Bioimaging and Therapy.

Persistent luminescence phosphors (PLPs) can remain luminescent after excitation ceases and have been widely explored in bioimaging and therapy since 2007. In bioimaging, PLPs can efficiently avoid tissue autofluorescence and light scattering interference by collecting persistent luminescence signals after the end of excitation. Outstanding signal-to-background ratios, high sensitivity, and resolution have been achieved in bioimaging with PLPs. In therapy, PLPs can continuously produce therapeutic molecules such as reactive oxygen species after removing excitation sources, which realizes sustained therapeutic activity after a single dose of light stimulation. However, most PLPs are activated by ultraviolet or visible light, which makes it difficult to reactivate the PLPs in vivo, particularly in deep tissues. In recent years, excitation sources with deep tissue penetration have been explored to activate PLPs, including X-ray, γ-ray, and ultrasound. Researchers found that various inorganic and organic PLPs can be activated by X-ray, γ-ray, and ultrasound, making these PLPs valuable in the imaging and therapy of deep-seated tumors. These X-ray/γ-ray/ultrasound-activated PLPs have not been systematically introduced in previous reviews. In this review, we summarize the recently developed inorganic and organic PLPs that can be activated by X-ray, γ-ray, and ultrasound to produce persistent luminescence. The biomedical applications of these PLPs in deep-tissue bioimaging and therapy are also discussed. This review can provide instructions for the design of PLPs with deep-tissue-renewable persistent luminescence and further promote the applications of PLPs in phototheranostics, noninvasive biosensing devices, and energy harvesting.

Amorphous In–Al–Sn–O Thin Film Transistors and Their Application in Optoelectronic Artificial Synapses

AbstractIn‐Al‐Sn‐O (IATO) is a very promising novel amorphous oxide as the active layer of thin film transistors (TFTs). Herein, IATO TFTs are first fabricated with the effects of annealing on IATO films and TFTs being studied. The IATO films possessed amorphous structure, flat surface morphology, high visible light transmittance, and wide optical bandgap ≈4.20 eV before and after annealing even at 400 °C. The minimal surface roughness and internal defects are obtained for the 300 °C annealed IATO film. Correspondingly, the 300 °C annealed TFTs demonstrated the best overall performance including high saturation mobility (8.55 ± 0.62 cm2 V−1 s−1), low subthreshold swing (0.40 ± 0.07 V dec−1), ideal on/off current ratio (1.25 ± 0.09 × 108), and negligible hysteresis (0.23 ± 0.03 V) values. The 300 °C annealed TFTs are then applied in optoelectronic artificial synapses and exhibit typical synaptic properties, including excitatory postsynaptic current, paired‐pulse facilitation, and short‐term plasticity to long‐term plasticity conversion in response to light stimulation. The international Morse code and repetitive learning‐forgetting behavior of the human brain are also successfully simulated. In particular, an emotion‐memory efficiency model is proposed and the emotion effect on human memory efficiency is successfully imitated via the regulation of gate voltage.

Light-Responsive Smart Nanoliposomes: Harnessing the Azobenzene Moiety for Controlled Drug Release under Near-Infrared Irradiation.

The azobenzene moiety is an intriguing structure that deforms under UV and visible light, indicating a high potential for biomedical applications. However, its reaction to UV radiation is problematic because of its high energy and low tissue penetration. Unlike previous research on azobenzene structures in photoresponsive materials, this study presents a novel method for imparting photostimulation-responsive properties to liposomes by incorporating the azobenzene moiety and extending the light wavelength with up-conversion nanoparticles. First, the azobenzene structure was incorporated into a phospholipid molecule to create Azo-PSG, which could spontaneously form vesicle assemblies in aqueous solutions and isomerizes within 1 h of light exposure. Furthermore, orthogonal up-conversion nanoparticles with a core-shell structure were created by sequentially growing lanthanide rare earths in the shell layer, which efficiently converts near-infrared light into ultraviolet (400 nm) and blue-green (540 nm) light. Combining these core-shell structured up-conversion nanomaterials with Azo-PSG molecules resulted in the creation of a near-infrared light-responsive smart nanoliposome system. Under near-infrared light irradiation, UCNPs emit UV and blue-green light, causing conformational changes in Azo-PSG molecules that allow drug release within 6 h. The reversible structural shift of Azo-PSG in response to light stimulation holds enormous promise for improving drug release techniques. This novel technique also expands the usage of UV-responsive compounds beyond their constraints of low penetration and high biotoxicity, allowing for rapid medication release under NIR light.

In Situ Stimulus Response Study on the Acetylene/Ethylene Purification Process in MOFs.

Efficient removal of acetylene (C2H2) impurities from polymer-grade ethylene (C2H4) in a simple, clean manner remains a challenging goal in industry. The use of porous materials such as metal-organic frameworks (MOFs) is promising for this aim but the acquisition of high purification performance is still hindered by few knowledge on the purification process because the previous conclusions were derived basically from the non-breakthrough tests or ignored the influence of structural difference (crystal structure, morphology, or defect). Here we propose an unprecedented in situ stimulus response strategy to minimize the influence of structural difference, obtain the gas-loading crystal structures of the same MOF before and after light or heat stimulation, directly observe the evolution of pore charge distribution and pore×××gas interactions under light/heat induction, and finally summarizes the favorable structure for highly efficient purification of C2H4. This study opens a new route to understand the relationship between the structure and separation performance for porous materials.

In Situ Stimulus Response Study on the Acetylene/Ethylene Purification Process in MOFs

Efficient removal of acetylene (C2H2) impurities from polymer‐grade ethylene (C2H4) in a simple, clean manner remains a challenging goal in industry. The use of porous materials such as metal–organic frameworks (MOFs) is promising for this aim but the acquisition of high purification performance is still hindered by few knowledge on the purification process because the previous conclusions were derived basically from the non‐breakthrough tests or ignored the influence of structural difference (crystal structure, morphology, or defect). Here we propose an unprecedented in situ stimulus response strategy to minimize the influence of structural difference, obtain the gas‐loading crystal structures of the same MOF before and after light or heat stimulation, directly observe the evolution of pore charge distribution and pore×××gas interactions under light/heat induction, and finally summarizes the favorable structure for highly efficient purification of C2H4. This study opens a new route to understand the relationship between the structure and separation performance for porous materials.

Color Recognition Achieved in Multiwavelength Controlled Plasmonic Optoelectronic Memristor for Neuromorphic Visual System

AbstractAn optoelectronic synaptic device with the color‐recognition ability is highly desired for achieving the high‐efficient neuromorphic color visual system. In order to realistically implement the functionality of retina (i.e., bipolar cells and cones photoreceptors), the exploration of multiwavelength controlled optoelectronic synaptic devices with fully light tunable ability would be sorely needed. Here, a multiwavelength controlled plasmonic optoelectronic memristor based on the size‐dependent localized surface plasmon resonance (LSPR) of metallic nanostructures is developed. The distinguishable red (R), green (G), and blue (B) light response behaviors can be achieved in this single device, which enables the realization of color image perception and memory functions. The RGB light‐strengthened synaptic plasticity can be depressed by ultraviolet light stimulations, relying on the effects of LSPR and optical excitation in WOx:Ag nanocomposites. Moreover, the visual attention for color (color discrimination) is realized in this memristor, which promotes the improvement of recognition accuracy during the color image recognition process. A new approach in developing multiwavelength controlled synaptic devices is provided here for highly efficient neuromorphic vision.

Effectiveness of add-on acetazolamide in children with drug-resistant CHD2-related epilepsy and in a zebrafish CHD2 model.

CHD2-related epilepsy is characterized by early-onset photosensitive myoclonic epilepsy with developmental delay and a high rate of pharmacoresistance. We sought to evaluate the efficacy of acetazolamide (ACZ) in CHD2-related epilepsy, due to ACZ's unexpected efficacy in our first patient harboring a pathogenic CHD2 variant. We collected patients from different Eastern European countries with drug-resistant CHD2-related epilepsy who were then treated with ACZ. Patients underwent video EEG before and during ACZ treatment. In a zebrafish model of CHD2-related epilepsy, ictal-like events were recorded 5 days post-fertilization after overnight ACZ exposure. Developmental delay preceded the onset of seizures in 10 of the 12 patients. Four had ataxia, and 6 exhibited autistic features. Seizures, primarily myoclonic, began at an average age of 3.4 years and were photosensitive in all 12 patients. Add-on ACZ treatment controlled photosensitive seizures in all patients: 6 became seizure-free, and in the remaining 6, seizure frequency decreased by over 75%. Four patients transitioned to ACZ monotherapy. The median follow-up was 13 months. In the zebrafish model, ACZ exposure reduced ictal-like events by 72%. ACZ, a well-tolerated and cost-effective medication, could be a good option for CHD2-related epilepsy, predominantly manifesting with myoclonic seizures and photosensitivity. PLAIN LANGUAGE SUMMARY: Epilepsy associated with CHD2 mutations is often pharmacoresistant and associated with developmental delay and eventually ataxia. There are several generalized seizure types, including generalized tonic-clonic seizures, but the most characteristic are jerks triggered by light stimulation. We collected 12 patients who received acetazolamide, a drug usually given as a diuretic and registered as a mild antiseizure medication. All jerks triggered by light disappeared while the frequency of spontaneous seizures decreased by over 75%. Further studies are needed to confirm this promising finding and identify the mechanism by which an old compound seems to have such a specific antiseizure effect.

Double perovskite CaSrMSbO6(M = La, Gd, Y): Bi3+ phosphors for multifunctional application

Bi3+-doping luminescent materials have recently evoked considerable interest in versatile applications. In this work, we have developed a series of Bi3+-activated CaSrMSbO6(M = La, Gd, Y) phosphors with double perovskite structures, exhibiting blue emission from 350 nm to 500 nm. The emission spectral position and intensity of Bi3+ ions can be tuned by changing excitation wavelength and doping concentrations. The relationship between the local crystal field environment and the luminescence properties is comprehensively analyzed. Importantly, optical temperature properties of CaSrLaSbO6: Bi3+ were investigated and were found to reach a maximum relative sensitivity of 4.57 % K−1 at 298 K. Furthermore, the anti-counterfeiting ink was prepared using CaSrLaSbO6: Bi3+ phosphors, and it showed tunable emission under different light stimulation. These results indicate that CaSrLaSbO6: Bi3+ phosphors have application potential in optical temperature sensing and anti-counterfeiting.

Molecular responses in the intestine of Atlantic salmon (Salmo salar) following light and diet stimulation of smoltification: Potential molecular markers for a seawater-ready smolt

The transfer to seawater (SW) represents a critical stage in the production of Atlantic salmon. The success of the transfer links with the optimal development of hypo-osmoregulatory capacities during smoltification. While various strategies are adopted in aquaculture to stimulate smoltification, considerable fish loss still occurs after transfer to sea cages. Therefore, we investigated the molecular responses in the anterior and posterior intestine of Atlantic salmon, following 1) a photoperiod treatment (24 h light (L):0 h dark (D) → 24 L:0D vs. 7 L:17D → 24 L:0D) and 2) dietary treatment (regular feed or feed enriched with a salt mix/tryptophan), combined with, or without a photoperiodic treatment in freshwater (FW), to evaluate how intestinal osmoregulatory mechanisms are modulated by these treatments, and to identify potential intestinal markers indicative of a SW-ready smolt. Using quantitative real-time PCR (qPCR), we investigated transcript levels of transporters and channels involved in ion movements through the enterocytes, tight junction components, and receptors (i.e., calcium-sensing receptor and prolactin receptor). The two intestinal regions showed different gene profiles and responsiveness towards the experimental treatments. In the anterior intestine, the exposure to short photoperiod (7 L:17D) upregulated Na+/K+ − ATPase subunit alpha 1c (nkaα1c), Na+/K+/2Cl− cotransporter 1 (nkcc1), Na+/K+/2Cl− cotransporter 2 (nkcc2), Cl−/HCO3− exchanger Slc26a6 (slc26a6), and cystic fibrosis transmembrane conductance regulator I (cftrI), in FW and SW. Also, Na+/K+ − ATPase subunit alpha 1b (nkaα1b), occludin (ocln), and prolactin receptor (prlr) were upregulated in FW and claudin 15 (cldn15) in SW groups exposed to this photoperiod. The posterior intestine was less responsive to the experimental treatments, although upregulation of nkcc1, nkcc2, slc26a6, and cftrI was observed in FW in the short photoperiod groups. Hence, our findings show that exposure to a winter signal in FW more effectively activates hypo-osmoregulatory mechanisms in the intestine of Atlantic salmon, where a coordinated and complementary role of the anterior and posterior intestine ensures optimal SW processing. Dietary treatment had a positive but more marginal effect on the regulation of the genes investigated, mainly enhancing the impact of short photoperiod when the two treatments were combined. Overall, we propose the apical Na+/K+/2Cl− cotransporter, nkcc2, and the apical Cl−/HCO3− exchanger, slc26a6, as potential FW molecular markers in the anterior intestine to assess “SW-readiness” in Atlantic salmon smolts.

Optically Stimulated Luminescence (OSL) characteristics of four fluorite samples under green light stimulation

This study investigates the OSL properties of four natural fluorite color varieties (green, purple, blue-yellow banded and yellow) under green light stimulation. Thermoluminescence reveals two peaks, with the green sample showing the strongest glow. OSL exhibits a fast initial decay followed by a slower one, with phototransfer observed in purple and yellow. OSL intensity is linear with dose (1-30 Gy) for most samples, except yellow. Curve fitting using a first order kinetics model suggests multiple OSL components (between 3 and 5). Preheat treatment at 100°C increases the very fast components (thermal transfer). Anomalous fading shows rapid initial decay followed by a slower one.

A Self-Driven Ga2O3 Memristor Synapse for Humanoid Robot Learning.

In recent years, the rapid development of brain-inspired neuromorphic systems has created an imperative demand for artificial photonic synapses that operate with low power consumption. In this study, a self-driven memristor synapse based on gallium oxide (Ga2O3) nanowires is proposed and demonstrated successfully. This memristor synapse is capable of emulating a range of functionalities of biological synapses when exposed to 255nm light stimulation. These functionalities encompass peak time-dependent plasticity, pulse facilitation, and memory learning capabilities. It exhibits an ultrahigh paired-pulse facilitation index of 158, indicating exceptional learning performance. The transition from short-term memory to long-term memory can be attributed to the remarkable relearning capabilities. Furthermore, the potential applications of the memristor synapse is showcased through the successful manipulation of a humanoid intelligent robot. Upon establishing artificial intelligence (AI) systems, the control commands originating from the synaptic device can drive the humanoid robot to perform various actions. Based on the memristor synapses, the autonomous feedback system of the humanoid robot facilitates a good collaboration between robotic actions and bio-inspired light perception. Therefore, this research opens up an effective way to advance the development of neuromorphic computing technologies, AI systems, and intelligent robots that demand ultra-low energy consumption.

Responsive porous microneedles with riboflavin ocular microinjection capability for facilitating corneal crosslinking

Riboflavin-5-phosphate (riboflavin) is the most commonly used photosensitizer in corneal crosslinking (CXL); while its efficient delivery into the stroma through the corneal epithelial barrier is challenging. In this paper, we presented novel responsive porous microneedles with ocular microinjection capability to deliver riboflavin controllably inside the cornea to facilitate CXL. The microneedle patch was composed of Poly (N-isopropyl acrylamide) (PNIPAM), graphene oxide (GO), and riboflavin-loaded gelatin. After penetrating the cornea by the stiff and porous gelatin needle tip, the photothermal-responsive characteristic of the PNIPAM/GO hydrogel middle layer could realize the contraction of the gel under the stimulation of near-infrared light, which subsequently could control the release of riboflavin from the backing layer into the cornea stromal site both in vitro and in vivo. Based on the microneedles system, we have demonstrated that this microinjection technique exhibited superior riboflavin delivery capacity and treatment efficacy to the conventional epithelial-on protocol in a rabbit keratoconus model, with benefits including minimal invasiveness and precise administering. Thus, we believe the responsive porous microneedles with riboflavin ocular microinjection capability are promising for clinical corneal crosslinking without epithelial debridement.

Light-adapted flicker-optoretinography based on raster-scan optical coherence tomography towards clinical translation.

Optoretinography (ORG) is a promising non-invasive and objective technique for assessing retinal function by measuring its response to light stimulation. Optical coherence tomography (OCT) has emerged as a promising tool for implementing ORG due to its three-dimensional imaging capabilities, high sensitivity to nanometer-scale changes induced by light stimulation, and clinical availability. Although ORG has proven feasible in laboratory settings, research-grade OCT systems lack satisfactory usability and cost-effectiveness to be clinically viable. Standard clinical raster-scan OCT systems, with their limited imaging speed, fall short of the requirements for measuring rapid ORG responses. To bridge this gap, we introduce a flicker-ORG modality based on a raster-scan OCT system that resembles standard clinical OCT. This system overcomes speed limitations through an innovative two-stage scanning protocol coupled with a 600 kHz swept source, enabling repeated volume imaging and precise retinal activity measurements over a finite area. Additionally, the light-adapted ORG strategy eliminates the need for dark adaptation, allowing examinations under photopic conditions and thus improving patient compliance. We tested this new ORG method by measuring flicker-induced photoreceptor responses in five healthy subjects. The results demonstrated high repeatability and revealed dependencies of the ORG response on flicker frequency and retinal eccentricity. These findings, combined with the system's utility, cost-effectiveness, and ease of integration into existing technologies, underscore its substantial potential for clinical application.