A5087014380- Neuroscience and Neural Engineering
- Advanced Memory and Neural Computing
- Photoreceptor and optogenetics research
- Plasmonic and Surface Plasmon Research
- EEG and Brain-Computer Interfaces
- Digital Holography and Microscopy
- Advanced Fluorescence Microscopy Techniques
- Optical Coatings and Gratings
- CCD and CMOS Imaging Sensors
- Connexins and lens biology
- Ion channel regulation and function
- Gold and Silver Nanoparticles Synthesis and Applications
- Orbital Angular Momentum in Optics
- Retinal Development and Disorders
- Retinal and Macular Surgery
- Microfluidic and Bio-sensing Technologies
- Retinal Imaging and Analysis
- Ocular and Laser Science Research
- Neurobiology and Insect Physiology Research
- Neuroscience and Neuropharmacology Research
- Ocular Disorders and Treatments
- Advanced Fiber Optic Sensors
- Visual perception and processing mechanisms
- Photonic Crystals and Applications
- Tactile and Sensory Interactions
Stanford University
2015-2023
University of Oregon
2022-2023
Baylor University
2013-2015
Abstract Localized stimulation of the inner retinal neurons for high-acuity prosthetic vision requires small pixels and minimal crosstalk from neighboring electrodes. Local return electrodes within each pixel limit crosstalk, but they over-constrain electric field, thus precluding efficient with subretinal smaller than 55 μm. Here we demonstrate a high-resolution based on novel design photovoltaic array, where field confinement is achieved dynamically, leveraging adjustable conductivity...
Retinal prostheses aim to restore sight by electrically stimulating the surviving retinal neurons. In clinical trials of current implants, prosthetic visual acuity does not exceed 20/550. However, provide meaningful restoration central vision in patients blinded age-related macular degeneration (AMD), should be at least 20/200, necessitating a pixel pitch about 50 µm or lower. With such small pixels, stimulation thresholds are high due limited penetration electric field into tissue. Here, we...
Abstract High-resolution visual prostheses require small, densely packed pixels, but limited penetration depth of the electric field formed by a planar electrode array constrains such miniaturization. We present novel honeycomb configuration an with vertically separated active and return electrodes designed to leverage migration retinal cells into voids in subretinal space. Insulating walls surrounding each pixel decouple from width aligning vertically, enabling decrease size down cellular...
High-resolution prosthetic vision requires dense stimulating arrays with small electrodes. However, such miniaturization reduces electrode capacitance and penetration of electric field into tissue. We evaluate potential solutions to these problems subretinal implants based on utilization pillar electrodes.To study integration three-dimensional (3D) retinal tissue, we fabricated varying diameter, pitch, height, implanted beneath the degenerate retina in rats (Royal College Surgeons, RCS)....
Abstract Objective. To restore central vision in patients with atrophic age-related macular degeneration, we replace the lost photoreceptors photovoltaic pixels, which convert light into current and stimulate secondary retinal neurons. Clinical trials demonstrated prosthetic acuity closely matching sampling limit of 100 μ m hence smaller pixels are required for improving visual acuity. However, flat bipolar electric field penetration depth photodiode responsivity significantly decrease,...
Currently, cellular action potentials are detected using either electrical recordings or exogenous fluorescent probes that sense the calcium concentration transmembrane voltage. Ca imaging has a low temporal resolution, while voltage indicators vulnerable to phototoxicity, photobleaching, and heating. Here, we report full-field interferometric of individual by detecting movement across entire cell membrane. Using spike-triggered averaging movies synchronized with recordings, demonstrate...
In patients blinded by geographic atrophy, a subretinal photovoltaic implant with 100 µm pixels provided visual acuity closely matching the pixel pitch. However, such flat bipolar cannot be scaled below 75 µm, limiting attainable acuity. This limitation can overcome shaping electric field 3-dimensional (3-D) electrodes. particular, elevating return electrode on top of honeycomb-shaped vertical walls surrounding each extends vertically and decouples its penetration into tissue from width....
Abstract Localized stimulation of the inner retinal neurons for high-acuity prosthetic vision requires small pixels and minimal cross-talk from neighboring electrodes. Local return electrodes within each pixel limit crosstalk, but can over-constrain electric field, thus precluding efficient with subretinal smaller than 50 μm. Here we demonstrate high-resolution based on a novel design photovoltaic array, where field confinement is achieved dynamically, leveraging adjustable conductivity...
To restore vision in patients who lost photoreceptors due to retinal degeneration, we developed a photovoltaic subretinal prosthesis which converts light into pulsed electric current, stimulating the inner neurons. Visual information is projected onto retina by video goggles using near-infrared (880nm) light. This design avoids use of bulky electronics and wiring, thereby greatly reducing surgical complexity allows scaling implants thousands electrodes. We found that similarly normal vision,...
Abstract Objective To restore central vision in patients with atrophic age-related macular degeneration, we replace the lost photoreceptors photovoltaic pixels, which convert light into current and stimulate secondary retinal neurons. Clinical trials demonstrated prosthetic acuity closely matching sampling limit of 100 μm hence smaller pixels are required for improving visual acuity. However, flat bipolar electric field penetration depth photodiode responsivity significantly decrease, making...
We study the resonant wavelength in plasmonic nanograting structures. Plasmonic devices can be used as sensors to detect refractive indices of surrounding dielectric media. find that increase nanogroove depth will sensitivity and width has a little impact on sensitivity. The numerical simulation results from FDTD method agree with phase-matching condition for surface plasmon waves.
We study the resonant wavelength in plasmonic nanograting structure covered by dielectric media. The increase nanogroove depth will sensitivity and width has a little impact on sensitivity.
Electrical synapses are neuronal gap junction (GJ) channels associated with a macromolecular complex called the electrical synapse density (ESD), which regulates development and dynamically modifies transmission. However, proteomic makeup molecular mechanisms utilized by ESD that direct formation not well understood. Using Mauthner cell of zebrafish as model, we previously found intracellular scaffolding protein ZO1b is member ESD, localizing postsynaptically, where it required for GJ...
Abstract In patients blinded by geographic atrophy, subretinal photovoltaic implant with 100µm pixels provided visual acuity closely matching the pixel pitch. However, such flat bipolar cannot be scaled below 75µm, limiting attainable acuity. This limitation can overcome shaping electric field 3-dimensional electrodes. particular, elevating return electrode on top of honeycomb-shaped vertical walls surrounding each extends vertically and decouples its penetration into tissue from width....
High-speed quantitative phase microscopy enables full-field imaging of cellular deformations during action potential. In spiking HEK cells, displacements up to 3nm (0.9mrad) have been observed, and they match the time course electrical recordings.
We demonstrate the controlled transport of simultaneous nano-scale particles across a patterned gold film. Nanopillars onto surface load nearby plasmonic conveyor belts formed from C-shaped engravings.
We study the cavity effect of a dielectric layer on nanograting structures. Varying thickness thin causes waves in to oscillate between constructive and destructive interference.
The localized plasmon mode of the trapped metal nanoparticle shifts as it draws closer to metallic substrate. This dynamically modifies its interaction energy with trap and force at operating wavelength.
Wide-field interferometric imaging systems can detect mechanical deformations of a cell during an action potential (AP), such as in quantitative phase microscopy, which is highly sensitive to the changing optical path length. This enables non-invasive optophysiology spiking cells without exogeneous markers, but high-fidelity requires averaging large number spikes synchronized by electrical recordings. We have developed new iterative methods for detecting single APs from microscopy cells,...