A novel bienzyme glucose biosensor based on three-layer Au–Fe3O4@SiO2 magnetic nanocomposite

• DOI: 10.1016/j.snb.2011.06.076
• Publication Date: 2011-07-05T22:35:19Z
• Authors: Xiaojun Chen; Jinwei Zhu; Zixuan Chen; Chenbin Xu; Yan Wang; Cheng Yao
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract The magnetic core–shell Au–Fe3O4@SiO2 nanocomposite was prepared by layer-by-layer assembly technique and was used to fabricate a novel bienzyme glucose biosensor. Glucose oxidase (GOD) and horseradish peroxidase (HRP) were simply mixed with Au–Fe3O4@SiO2 nanocomposite and cross-linked on the ITO magnetism-electrode with nafion (Nf) and glutaraldehyde (GA). The modified electrode was designated as Nf–GOD–HRP/Au–Fe3O4@SiO2/ITO. The effects of some experimental variables such as the pH of supporting electrolyte, enzyme loading, the concentration of the mediator methylene blue (MB) and the applied potential were investigated. The electrochemical behavior of the biosensor was studied using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and chronoamperometry. Under the optimized conditions, the biosensor showed a wide dynamic range for the detection of glucose with linear ranges of 0.05–1.0 mM and 1.0–8.0 mM, and the detection limit was estimated as 0.01 mM at a signal-to-noise ratio of 3. The biosensor exhibited a rapid response, good stability and anti-interference ability. Furthermore, the biosensor was successfully applied to detect glucose in human serum samples, showing acceptable accuracy with the clinical method.