Resonant Based Light Amplification for High-Resolution Optical Retinal Prosthesis

Gal Shpun The Alexander Kofkin Faculty of Electrical Engineering, Bar-Ilan University, Ramat Gan, Israel Optometry and Visual Science, Faculty of Life Science, Bar-Ilan University, Ramat Gan, Israel BINA - Bar Ilan Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel

Optogenetic based retinal prostheses show promises for the restoration of sight for patients with retinal degeneration. However, current technology is based on projecting high-power blue light, which may damage the intraocular tissue. Here, we present a novel device based on a 2D array of conjugated local plasmon resonance (LPR), created by noble metal nanoparticles, for local enhancement of light field within the neuron membrane, aimed at significantly decreasing of the light-threshold needed for the neural activation. The nanoparticles` geometrical dimensions and their inter-particles distance were optimized to specifically enhance the light power within the neuron membrane at λ=476nm (comply with ChR2, a light-gated cation channel). A combined numerical simulation tool based on CST MW and COMSOL Multiphysics softwares was developed to calculate the local amplification of the light-power within the neuronal membrane and the induced increase in the membrane’s current and voltage response to light activation. The results show that light intensity was amplified by up to 6-folds of magnitude, allowing a decrease of one order of magnitude in the neural threshold intensity-duration curve. This approach opens novel opportunities for future application of neural prostheses in general and for the retinal prostheses in particular.