Polymeric microfabricated electrochemical nanoprobe with addressable electrodes

We present a polymeric microfabricated electrochemical nanoprobe (MEN) with nanometer-scale electrodes fabricated using standard photolithography. The probe and the electrodes are formed by embedding nanometer-thick metal lines between two layers of UV curable adhesive polymers, followed by dicing and detaching the MENs from the substrate. The cutting plane obtained after dicing constitutes the tip of the MENs. The thicknesses of the spin-coated polymer and of the deposited metal determine the thickness of the probe and the electrodes, respectively, and can be precisely controlled. Several polymers were characterized, including SU-8 and photosensitive polyurethanes which were found to be optimal. MENs with two and four electrodes were fabricated. The MENs were characterized by cyclic voltammetry. The reproducibility of the MENs for electrochemical measurements was optimized and the sensitivity was significantly enhanced by the controlled electrodeposition of palladium nanocrystals yielding a greater active electrode area. These MENs may be functionalized and used to analyse the concentration of chemicals by placing the MEN above them.