Direct Electrochemistry and Electrocatalytic Behavior of Horseradish Peroxidase on Attapulgite Clay Modified Electrode

Abstract

A novel third-generation hydrogen peroxide (H₂O₂) biosensor was developed by immobilizing horseradish peroxidase (HRP) on a biocompatible attapulgite (ATP) modified glassy carbon (GC) electrode. The ATP could provide a biocompatible microenvironment for enzyme molecules, greatly amplify the coverage of HRP molecules on the electrode surface, and most importantly facilitate the direct electron transfer between HRP and the electrode. The biosensor construction process was followed by atomic force microscopy (AFM). Cyclic voltammetry was employed to characterize the properties of the biosensor. A linear calibration plot of the enzyme electrode was obtained over the range of 5 μM to 0.3 mM for H₂O₂ with a detection limit of 5 μM. Furthermore, the biosensor showed high sensitivity, good reproducibility, and fine long-term stability.