Direct electrodeposition of gold nanoparticles onto indium/tin oxide film coated glass and its application for electrochemical biosensor

A novel electrochemical deposition method for growth of gold nanoparticles (GNPs) on indium tin oxide (ITO) thin film coated glass was investigated. The resulting electrode surface was characterized by SEM, UV–Vis spectroscopy and electrochemical methods. The GNPs directly attached on the electrode surface with a quasi-spherical shape and their sizes of diameters were in the range of 20–35 nm with a quite symmetric distribution. With increasing electrodeposition cycles of cyclic voltammetry, the density of GNPs on ITO electrode surface was increased. The potential utility of the GNPs modified ITO electrode was investigated. Superoxide dismutase (SOD) was successfully immobilized on GNPs modified ITO electrode and the direct electron transfer between enzyme and electrode surface realized. The enzyme electrode exhibited a rapid and high response to superoxide anion.