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Fabrication and Characterization of Platinum-Iridium Electrodes with Micro-Structured Surfaces For Neural Stimulation Applications

Published online by Cambridge University Press:  15 March 2011

Sachin S. Thanawala ,
Daniel G. Georgiev ,
Afzal Khan ,
Ronald J. Baird  and
Gregory Auner
Sachin S. Thanawala
Affiliation:
Department of Biomedical Engineering, Wayne State University, Detroit, MI-48202
Daniel G. Georgiev
Affiliation:
Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI-48202
Afzal Khan
Affiliation:
Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI-48202
Ronald J. Baird
Affiliation:
Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI-48202
Gregory Auner
Affiliation:
Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI-48202
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Abstract

Controlled structuring of electrode surfaces on a microscopic scale is expected to decrease the impedance and improve the current injection capabilities of neural stimulation electrodes. We have identified conditions for the fabrication of micro-bumps on platinum-iridium alloy surfaces by means of KrF excimer laser (λ=248nm) irradiation under ambient conditions. A regular array of closely spaced micro-bumps with diameters of about 5µm and heights of about 3µm was generated on the polished face of a platinum-20%iridium wire with a diameter of 75µm. A projection system with a demagnification factor of 9 was used to image a mask with a pattern of circular-holes on the polished face of the wire. Several thousand pulses at a repetition rate of 10Hz and a fluence of 3.0 J/cm2 were applied to produce the micro-bumps. The modified electrode surfaces were studied by optical microscopy and scanning electron microscopy, and the results show the formation of micro-bumps of reproducible shape. Simple two-electrode AC impedance measurements in physiological saline in the frequency range of interest to neural stimulation applications show a considerable decrease in the impedance of micro-structured electrodes with respect to the impedance of a polished electrode.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 820: Symposia O/R – Nanoengineered Assemblies and Advanced Micro/Nanosystems , 2004 , O8.11
Copyright
Copyright © Materials Research Society 2004

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