Titanium Nitride Nanotubes Electrodes for Chronic Neural Stimulation

For the first time, this paper presents corrosion resistant and high-capacity implantable titanium nitride (TiN) nanotubes electrodes for the application of neural probes. Traditionally, the TiN electrodes are prepared using reactive sputtering techniques and have limited surface areas. To research smaller electrodes to minimize tissue damage, high aspect ratio TiN nanotube structures with high surface areas were fabricated using electrochemical anodization of Ti wires followed by high-temperature nitration. The specific charge capacity of nanoporous TiN was found proportionally with the surface area and pore size. Compared to tungsten electrode, the impedance and morphology of nanoporous TiN was found stable in an accelerated stress test (at an elevated temperature in phosphorous buffered solution).