A Mediatorless Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase Immobilized in Tin Oxide Sol‐Gel Film

Abstract

Abstract A novel unmediated hydrogen peroxidase biosensor was developed by immobilizing horseradish peroxidase (HRP) into a tin oxide sol‐gel film at a glass carbon electrode surface. Morphology of the sol‐gel film and HRP entrapped in the sol‐gel film were characterized by transmission electron microscopy (TEM) and Fourier‐transform infrared (FTIR) spectroscopy, respectively, showing the uniform porous network structure in the presence of nano‐SnO2 particles and the retention of the enzymatic bioactivity with its native secondary structure. The direct electrochemistry of HRP incorporated in the film was investigated using cyclic voltammetry. The biosensor exhibited good stability and electrocatalytic activity toward the reduction of hydrogen peroxide. The linear concentration range of the biosensor was from 0.01 mM to 0.25 mM. The apparent Michaelis‐Menten constant K M app was estimated to be 0.166 mM.