Purchase this article with an account.
M. D. Gingerich, D. B. Shire, J. L. Wyatt, J. F. Rizzo; Development Toward a Flexible Passive Penetrating Electrode Array Technology for a Subretinal Prosthesis. Invest. Ophthalmol. Vis. Sci. 2007;48(13):673.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
This work is related to the efforts of the Boston Retinal Implant Project to develop a sub-retinal prosthesis to restore vision to the blind. The specific purpose of this presentation is to describe our efforts to develop microfabricated penetrating post structures on polyimide-based flexible carriers, creating a penetrating electrode array that will place the stimulating electrodes nearer the target cells and thereby potentially decrease the threshold current.
Several sizes of penetrating posts were designed in CAD including: 10, 20, and 40 µm diameters. The penetrating posts were formed by adapting and optimizing a standard SU-8 fabrication process which included: 1) spin-coating SU-8 on a polyimide-coated silicon carrier wafer, 2) soft-baking, 3) UV exposure to a passive post pattern, 4) post-exposure baking, 5) developing away the unexposed SU-8, and finally, 5) high-temperature curing of the resulting structures for improved mechanical stability and adhesion to the underlying polyimide. The height of the posts was determined by the thickness to which the SU-8 was spin-coated. The process was optimized by systematically varying the process parameters including spin speed, exposure dose, bake and develop times.
A microfabrication process has been developed which can produce structures of 70 µm in height and as small as 10 µm in diameter, as shown in the Figure. Penetrating posts of three diameters have been fabricated on flexible polyimide carriers and have demonstrated good adhesion and mechanical properties in handling abrasion tests.
A means of fabricating SU-8-based passive posts on flexible polyimide substrates which can be implanted into the subretinal space has been developed. These structures may be used for in vivo histological and physiological studies.
This PDF is available to Subscribers Only