ELECTRODEPOSITED NOBLE METAL OXIDE NEURAL ELECTRODES

The development of electrodeposited noble metal oxides as low-impedance, high-charge injection coatings for neural recording and stimulating electrodes is proposed. The coatings are based on iridium and ruthenium oxides. The objective is to develop electrodeposition processes suitable for coating a broad range of metal substrates such as platinum, gold, PtIr-alloys, titanium, tungsten, and stainless steel, relevant to most neural recording and stimulating electrodes. The electrodeposited oxides will have impedance and charge injection characteristics similar to activated iridium oxide films (AIROFs), but will not require iridium metal substrates for electrode fabrication. In addition, mixed-metal oxides coatings will be evaluated as a means of increasing the reversible charge-injection capacity beyond that currently available with AIROF. The principal aims of Phase I are to conduct a detailed in vitro characterization of the electrochemical properties and stability of the coatings relevant to neural recording and stimulation, and to determine the biocompatibility of the coatings by histological evaluation of electrodes implanted in rabbit cortex. Phase H would evaluate the chronic functional stability of the coatings for recording and stimulation in the CNS and for stimulation of peripheral nerve and muscle. Applications in cortical stimulation and recording, pacing, pain management, peripheral nerve stimulation, and deep brain stimulation are anticipated.