A hydrogen peroxide sensor based on the peroxidase activity of hemoglobin immobilized on gold nanoparticles-modified ITO electrode

A novel ITO electrode surface modified with spherical and rod-shaped gold nanoparticles was prepared by a surfactant-assisted seeding growth approach, which provided a biocompatible matrix for the immobilization of hemoglobin (Hb). By electrochemical impedance measurements, gold nanoparticles modification and Hb immobilization on the electrode surfaces were characterized using [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ redox probe. Owing to the promoted electron transfer of Hb by gold nanoparticles, the Hb immobilized gold nanoparticles-modified ITO (Hb/Au/ITO) electrode exhibited an effective catalytic response to the reduction of H₂O₂ with good reproducibility and stability. The linear relationship existed between the catalytic current and the H₂O₂ concentration in the range of 1 × 10⁻⁵ to 7 × 10⁻³ M. The detection limit (S/N = 3) was 4.5 × 10⁻⁶ M.