Fabrication of nitrogen-incorporated nanodiamond ultra-microelectrode array for Dopamine detection

Well established silicon microfabrication technology and PECVD nanodiamond growth process enabled us to fabricate an ultra-microelectrode array (UMEA) for biosensing applications. The UMEA consists of 2500 nanodiamond elements in a square array surrounded by a layer of thermally grown SiO₂ on a highly doped silicon substrate. Fe(CN)₆^3?/4? redox couple was used for electrochemical characterization of the UMEA using cyclic voltammetry and gave us a steady state response consistent with hemispherical diffusion limited mass transport mechanism. Using the nanodiamond UMEA, we were also able to detect different concentrations of Dopamine in phosphate buffered saline (pH 7.4) without any surface functionalization. The cyclic voltammograms show a steady state response and a linear relationship between the limiting current and Dopamine concentration.