Activation of retinal ganglion cells using a biomimetic artificial retina

Abstract

Objective. Biomimetic protein-based artificial retinas offer a new paradigm for restoring vision for patients blinded by retinal degeneration. Artificial retinas, comprised of an ion-permeable membrane and alternating layers of bacteriorhodopsin (BR) and a polycation binder, are assembled using layer-by-layer electrostatic adsorption. Upon light absorption, the oriented BR layers generate a unidirectional proton gradient. The main objective of this investigation is to demonstrate the ability of the ion-mediated subretinal artificial retina to activate retinal ganglion cells (RGCs) of degenerated retinal tissue. Approach. Ex vivo extracellular recording experiments with P23H line 1 rats are used to measure the response of RGCs following selective stimulation of our artificial retina using a pulsed light source. Single-unit recording is used to evaluate the efficiency and latency of activation, while a multielectrode array (MEA) is used to assess the spatial sensitivity of the artificial retina films. Main results. The activation efficiency of the artificial retina increases with increased incident light intensity and demonstrates an activation latency of ∼150 ms. The results suggest that the implant is most efficient with 200 BR layers and can stimulate the retina using light intensities comparable to indoor ambient light. Results from using an MEA show that activation is limited to the targeted receptive field. Significance. The results of this study establish potential effectiveness of using an ion-mediated artificial retina to restore vision for those with degenerative retinal diseases, including retinitis pigmentosa.

Exploration: Nanoparticles in the Diagnosis and Treatment of Retinal Diseases

“…The development and optimization of artificial retina provide a new possibility for the treatment of retinal degeneration and irreversible damage caused by various causes [136][137][138]. Due to the biological characteristics of nanomaterials, they are increasingly used in various structures and links involved in retinal light signal conversion, in order to develop more sensitive, durable, and stable artificial retina [139][140][141].…”

Exploring retinal ganglion cells encoding to multi-modal stimulation using 3D microelectrodes arrays

“…Microelectrode arrays (MEA) offer a high spatiotemporal resolution for simultaneous electrophysiological recordings of multiple RGCs ( Marblestone et al, 2013 ). This versatile tool has demonstrated significant advancements in various areas, including visual encoding ( Fiscella et al, 2015 ; Pamplona et al, 2022 ) and visual prosthetics ( Corna et al, 2021 ; Greco et al, 2021 ). However, when applied to ex vivo retinal tissue, conventional planar MEAs face challenges due to the curved structure of the hemispherical retinal tissue, which can result in limited spatial resolution and potential hypoxia for neurons located at the bottom of the electrode.…”

Progressive Retinal Degeneration Increases Cortical Response Latency of Light Stimulation but Not of Electric Stimulation

“… 21 , 24 , 27 P23H has been used in multiple preclinical studies for experimental therapies. 10 , 28 – 30 …”