A novel hydrogen peroxide sensor based on horseradish peroxidase immobilized on colloidal Au modified ITO electrode

Abstract

A novel method to fabricate a hydrogen peroxide sensor was developed by immobilizing horseradish peroxidase (HRP) on colloidal Au modified ITO conductive glass support. The cleaned glass support was modified with (3-aminopropyl)trimethoxysilane (APTMS) first to yield an interface for the assembly of colloidal Au. Then 15 nm colloidal Au particles were chemisorbed onto the amine groups of the APTMS. Finally, HRP was adsorbed onto the surface of the colloidal Au. The immobilized HRP displayed excellent electrocatalytical response to the reduction of hydrogen peroxide. The performance and factors influencing the resulted biosensor were studied in detail. The resulted biosensor exhibited fast amperometric response (within 5 s) to H₂O₂. The detection limit of the biosensor was 8.0 μmol l⁻¹, and linear range was from 20.0 μmol l⁻¹ to 8.0 mmol l⁻¹. Furthermore, the resulted biosensor exhibited high sensitivity, good reproducibility, and long-term stability.