Electrodeposition of gold nanoparticles on indium/tin oxide electrode for fabrication of a disposable hydrogen peroxide biosensor

A novel disposable third-generation hydrogen peroxide (H2O2) biosensor based on horseradish peroxidase (HRP) immobilized on the gold nanoparticles (AuNPs) electrodeposited indium tin oxide (ITO) electrode is investigated. The AuNPs deposited on ITO electrode were characterized by UV–vis, SEM, and electrochemical methods. The AuNPs attached on the ITO electrode surface with quasi-spherical shape and the average size of diameters was about 25 nm with a quite symmetric distribution. The direct electron chemistry of HRP was realized, and the biosensor exhibited excellent performances for the reduction of H2O2. The amperometric response to H2O2 shows a linear relation in the range from 8.0 μmol L−1 to 3.0 mmol L−1 and a detection limit of 2 μmol L−1 (S/N = 3). The KMapp value of HRP immobilized on the electrode surface was found to be 0.4 mmol L−1. The biosensor indicates excellent reproducibility, high selectivity and long-term stability.