Soft, fuzzy, and bioactive conducting polymers for improving the chronic performance of neural prosthetic devices

Microfabricated electrodes for stimulating and recording signals from individual neurons have facilitated direct electrical connections with living tissue. While these devices have worked reasonably well in acute applications, chronically implanted electrodes have had more limited success [1,2]. To improve the long-term integration of these devices, coatings have been developed to accommodate the differences in mechanical properties, bioactivity, and mechanisms of charge transport between the engineered electronic device and living cells [3-10]. Conducting polymers can be directly deposited onto electrode surfaces with precisely controlled morphologies. The coatings lower the impedance of the electrodes and provide a mechanical buffer between the hard device and the soft tissue. These coatings can be tailored to incorporate and deliver pharmacological agents such as antiinflammatory drugs and neurotrophic factors. In vivo studies to date have shown that these coatings improve the long-term recording performance of cortical electrodes [11].