A direct-write nanofabrication technique was applied to fabricate high aspect ratio Pt needle
electrodes for site specific electrochemistry and electrophysiology. Non-passivated and
passivated (with a 10 nm thin insulating film) Pt needles having uniform radii as small as 100
nm and lengths over 30 μm were deposited on the exposed conductive ends of
ultramicroelectrodes to form extended needle electrodes. Diffusion limited current and its
dependence on the radius of the Pt needle were measured with linear sweep voltammetry …