Amperometric hydrogen peroxide biosensor based on a modified gold electrode with silver nanowires

A novel amperometric biosensor for the detection of hydrogen peroxide (H₂O₂) was prepared by immobilizing horseradish peroxidase (HRP) on highly dense silver nanowire (Ag-NW) film. The modified electrode was characterized using UV-Vis spectroscopy, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The electrochemical performances of the electrode were studied by cyclic voltammetry and chronoamperometry. The HRPs immobilized on the surface of Ag-NWs exhibited an excellent electrocatalytic response toward reduction of H₂O ₂. The resulting Ag-NW modified sensor showed a sensitivity of ~2.55 μA μM^-1 (correlation coefficient r = 0.9969) with a linear range of 4.8 nM-0.31 μM. Its detection limit was 1.2 nM with a signal-to-noise ratio of 3. The Michaelis-Menten constant K _M ^app and the maximum current density I _max of the modified electrode were 0.0071 mM and 8.475 μA, respectively. The preparation process of the proposed biosensor was convenient, and the resulting biosensor showed high sensitivity, low detection limit and good stability.