Direct electrochemistry of cytochrome c at a novel gold nanoparticles-attached NH2+ ions implantation-modified indium tin oxide electrode

A NH2+ ions implantation-modified indium tin oxide (NH2/ITO) electrode was prepared and the existence of amino group on the electrode was verified by FT-IR spectra and X-ray photoelectron spectroscopy analysis (XPS). The gold nanoparticles (AuNPs) have been fabricated on the surface of NH2/ITO electrode, resulting novel gold nanoparticles-attached NH2+ ions implantation-modified ITO (AuNPs/NH2/ITO) electrode, which could provide a biocompatible surface for the adsorption of cytochrome c (Cyt c). The Ultraviolet–visible (UV–vis) spectra indicated that Cyt c adsorbed on the AuNPs interface retained the native structure. Electrochemical impedance spectra (EIS) and cyclic voltammetric techniques were employed to evaluate the electrochemical behaviors of Cyt c. The surface of the AuNPs/NH2/ITO electrode was exhibited using the scanning electron microscopy (SEM) comparing with the surface of the gold nanoparticles-attached ITO electrode (AuNPs/ITO). We found that the functional surface of the NH2/ITO electrode resulted in a high AuNPs loading. The obtained Cyt c/AuNPs/NH2/ITO electrode gave an excellent electrocatalytic activity towards the reduction of H2O2, and the catalysis currents were proportional to the H2O2 concentration in the range of 2.0–300.0 μM with a detection limit of 0.5 μM (S/N = 3).