Direct electrochemistry and electrocatalysis of hemoglobin on a gold ion implantation-modified indium tin oxide electrode

In this paper, a gold nanoparticle-modified indium tin oxide electrode (Au/ITO) was prepared without the use of any cross-linker or stabilizer reagent. The prepared Au/ITO was used as a new platform to achieve the direct electron transfer between Hb and the modified electrode. The proposed electrode exhibited a pair of well-defined redox peaks with a formal potential of -0.073 V (vs. Ag/AgCl). The immobilized Hb showed excellent electrocatalytic activity toward H2O2 and the electrocatalytic current values were linear with the increasing concentration of H2O2 ranging from 1.0 x 10(-6) M to 7.0 x 10(-4) M. The detection limit was 2.0 x 10(-7) M (S/N = 3) and the Michaelis-Menten constant was calculated to be 0.2 mM. The proposed electrode also showed high selectivity, long-term stability, and good reproducibility.