Investigating the Interfacial Properties of Electrochemically Roughened Platinum Electrodes for Neural Stimulation

Platinum electrodes have been electrochemically roughened (roughness factors up to 430) and evaluated for use as neural stimulation electrodes. The roughened electrodes show superior interfacial properties with increasing surface roughness. The roughened electrode (fR = 250) has a charge injection limit of 1.0 mC cm–2 (400 μs pulse width), which is superior to that of titanium nitride (0.87 mC cm–2) but comparable to that of carbon nanotubes (1.0–1.6 mC cm–2). The surface roughness can also be optimized for different neural stimulation applications based on the available charge density at a particular pulse width of stimulation. The roughened platinum electrodes demonstrated good mechanical stability under harsh ultrasonication and electrochemical stability under continuous biphasic stimulation, indicating the potential of this biological interface to be safe and stable.