Improved chronic neural stimulation using high surface area platinum electrodes.

We report a novel nano-cluster platinum (NCPt) film that exhibits enhanced performance as an electrode material for neural stimulation applications. Nano-cluster films were deposited using a custom physical vapor deposition process and patterned on a flexible polyimide microelectrode array using semiconductor processing technology. Electrode performance was characterized in vitro using electrochemical impedance spectroscopy and compared with sputtered thinfilm platinum (TFPt) electrodes. We characterized electrode impedance, charge storage capacity, voltage transient properties, and relative surface area enhancement in vitro. Preliminary lifetime testing of the electrode reveals that the NCPt electrodes degrade more slowly than TFPt electrodes. The combination of material biocompatibility, electrochemical performance, and preliminary lifetime results point to a promising new electrode material for neural interface devices.