Biostability of micro-photodiode arrays for subretinal implantation

Haemmerle, Hugo and Kobuch, Karin and Kohler, Konrad and Nisch, Wilfried and Sachs, Helmut and Stelzle, Martin (2002) Biostability of micro-photodiode arrays for subretinal implantation. BIOMATERIALS, 23 (3). pp. 797-804. ISSN 0142-9612

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Abstract

Micro-photodiode arrays based on semiconductor Chip technology are being developed to replace degenerated photoreceptor cells in the retina. Electric Current is generated in tiny micro-photodiodes and delivered to the adjacent tissue by micro-electrodes. One of the main requirements of a sub-retinal implantable device is long-term stability versus corrosion in vivo (biostability). Biostability of micro-photodiode arrays (MPDA) was investigated in vitro and in vivo. No significant damage was found on chips immersed for up to 21 months in saline solution. Under in vivo conditions. however. the silicon oxide passivation layer of the chip was dissolved within a period of about 6-12 months. subsequently. the underlying silicon was corroded. In contrast, Stimulation electrodes consisting of titanium nitride were well preserved both in vitro and in vivo. The deterioration of the electrical properties of the micro-photodiodes correlated with the morphological damage observed. Strategies aiming at the development of an improved biostable encapsulation of neurotechnological implants have to be investigated and will be discussed briefly. (C) 2001 Elsevier Science Ltd. All rights reserved.

Item Type: Article
Uncontrolled Keywords: ELECTRICAL-STIMULATION; RABBIT RETINA; ELECTRODES; retina implant; micro-photodiode array; micro-electrode; electrical stimulation; biocompatibility; biostability
Subjects: 600 Technology > 610 Medical sciences Medicine
Divisions: Medicine > Lehrstuhl für Augenheilkunde
Depositing User: Dr. Gernot Deinzer
Date Deposited: 09 Nov 2021 12:39
Last Modified: 09 Nov 2021 12:39
URI: https://pred.uni-regensburg.de/id/eprint/40609

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