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N.Z. Mehenti, M.F. Marmor, M.S. Blumenkranz, S.F. Bent, H.A. Fishman; Development of a Flexible, Microfabricated Retinal Interface . Invest. Ophthalmol. Vis. Sci. 2004;45(13):4186.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Rigid, silicon–based retinal prostheses have produced visual sensations in blind subjects, but a flexible interface would provide more intimate and consistent contact with surviving retinal elements, and thereby allow higher visual resolution with lower power requirements. Our purpose is to use soft materials microfabrication technologies to develop flexible retinal chip interfaces that can achieve both electrical and neurotransmitter–based stimulation. Methods: Soft materials microfabrication methods with poly(dimethylsiloxane) (PDMS) were applied to design retinal interfaces based on electrical or chemical stimulation. Polymer micromachining techniques, including etching, metallization, and molding, were developed and optimized to create functional device layers. Spin casting and alignment bonding strategies were incorporated into the fabrication process to produce thin, integrated stimulation devices. Results: Integrated retinal interfaces were developed using PDMS by precisely tailoring the polymer microfabrication processes for the device layers. Electrically–based devices were fabricated using etching and metallization to deposit flexible, functional electrodes in a patterned array. Chemically–based devices employed microfabricated apertures in a thin membrane through which neurotransmitters could be controllably ejected from an underlying microfluidic channel. Both the microaperture diameter and membrane thickness could be controlled to a few microns, so that high–resolution stimulation as well as rapid delivery times could be achieved. Conclusions: Flexible retinal prosthetic chips are feasible and may allow for higher resolution stimulation as well as lower power requirements than achieved by current rigid devices. Our technology could potentially be extended to neural prosthetics in general.
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