Patterned iridium oxide film as neural electrode interface: Biocompatibility and improved neurite outgrowth with electrical stimulation.

Iridium (Ir) thin film was deposited on patterned titanium substrate by direct-current (DC) magnetron sputtering, and then activated in sulfuric acid (HSO) through repetitive potential sweeps to form iridium oxide (IrO) as neural electrode interface. The resultant IrO film showed a porous and open morphology with aligned microstructure, exhibited superior electrochemical performance and excellent stability. The IrO film supported neural stem cells (NSCs) attachment, proliferation and improved processes without causing toxicity. The patterned IrO films offered a unique system to investigate the synergistic effects of topographical cue and electrical stimulation on neurite outgrowth. Electrical stimulation, when applied through patterned IrO films, was found to further increase the neurite extension of neuron-like cells and significantly reorient the neurite alignment towards to the direction of stimulation. These results indicate that IrO film, as electrode-tissue interface is highly stable and biocompatible with excellent electrochemical properties.