Immobilization of Glucose Oxidase on Honeycomb-Like Three-Dimensional Nanoporous Gold for Amperometric Biosensing of Glucose

Abstract

Enzyme immobilization is one of the key factors in constructing high-performance bio-devices. Herein, a honeycomb-like three-dimensional nanoporous gold (3DHNPG) was electrodeposited by an one-step dynamic gas bubble template method for enzyme immobilization and enzyme-electrode fabrication. A CS/GOx/3DHNPG/Au electrode was prepared simply by cast-coating glucose oxidase (GOx) and chitosan (CS) successively on the 3DHNPG modified Au electrode and air-dried. The thus-prepared CS/GOx/3DHNPG/Au electrode responded linearly to glucose from 0.01 to 4.4 mM with a sensitivity of 166 μA mM⁻¹ cm⁻² and a limit of detection of 1.2 μM (first-generation biosensing mode). Due to the special porous structure of 3DHNPG with large specific surface area, as well as high catalytic activity for H₂O₂ oxidation, the sensitivity of CS/GOx/3DHNPG/Au electrode for glucose sensing is greatly enhanced, which is larger than those of CS/GOx/Au_plate/Au electrode, CS/GOx/Au electrode, and most reported GOx-based enzyme electrodes. This 3DHNPG-based enzyme electrode also worked well in the second-generation biosensing mode and as a bioanode in a monopolar biofuel cell. The 3DHNPG with great convenience in synthesis, outstanding biocompatibility and electron-conductibility may be an excellent matrix choice to immobilize biomolecules for constructing high-performance biodevices with promising applications.