Immobilization of Glucose Oxidase on Mesoporous Carbon for Bio-Electrodes

Abstract

The objective of this work was to understand glucose oxidase (GOx) immobilization on mesoporous carbon (MC) and the electrochemical performance of a bio-anode fabricated from GOx-immobilized MC. GOx, MC, and NaCl concentrations significantly influenced GOx immobilization. The GOx enzyme adsorption on MC increased by 2.3 times when the total solute concentration was increased from 20.5 to 164 mg mL-1. With the addition of NaCl (1.2 M), enzyme adsorption increased by 1.3 times compared to the control group. The bio-anode fabricated by GOx-immobilized MC displayed direct and surface-controlled redox reactions with an electron transfer coefficient (α) of 0.57 in 0.1 M phosphate buffer saline (PBS) solution (pH 7.0) with 10 mM glucose. GOx immobilization improved electron transfer between the electrolyte and the electrode surface with ΔEp shifting to 255 mV, compared to non-immobilized free enzymes on MC (ΔEp = 263 mV). The bio-electrode made by GOx-immobilized MC showed a current density of 227.37 μA cm-2.