Nanoporous Pt Microelectrode for Neural Stimulation and Recording: In Vitro Characterization

3D-nanoporous Pt (L 2 -ePt) films on multiarrayed microelectrodes electroplated from reverse micelle (L 2 ) phase were evaluated in vitro for neural cell stimulation and extracellular potential recording. Impedance, capacitance, and charge injection limit were measured for the L 2 -ePt electrodes with various surface specific areas, i.e., roughness factors. L 2 -ePt with a roughness factor of 223 showed optimum performances as neural stimulation and recording electrodes, and its electric characteristics were electrode impedance of 0.039 Ω cm 2 (1.17 kHz), electrode volume specific capacitance of 43 F cm −3 (1.17 kHz), and charge injection limit of 3 mC cm −2 (400 μs). L 2 -ePt showed higher mechanical strength than the conventional platinized Pt (Pt black).