Fabrication of Microelectrode Arrays Having High-Aspect-Ratio Microwires

A method is described for the fabrication of arrays of conducting, high-aspect-ratio microelectrodes. The microelectrode arrays are fabricated by electrochemical deposition of metals, including Ni, Pt, and Rh, in microchannel glass templates having parallel, uniform, hollow channels. The metals completely fill the hollow channels, yielding highly uniform, 5.5-μm-diameter microelectrodes with aspect ratios up to 500. The microelectrodes are electrically insulated from one another by the glass template and the surface area of each array is >1 cm2. The surface of the electrode arrays can be polished to provide an array of disk electrodes or it can be etched with acid to remove the glass surrounding the electrodes, exposing an array of bare, solid wires. The high-aspect-ratio microelectrode arrays were fabricated to provide the electrical interface with an intraocular retinal prosthesis. The properties of the solid wire, metal microelectrode arrays are also well-suited for use in electrochemical trace analysis and implantable neuro-prosthetic devices.