A Glucose Biosensor Based on Immobilization of Glucose Oxidase into 3D Macroporous TiO2

Abstract

Abstract3D macroporous TiO2 inverse opals have been derived from a sol‐gel procedure using polystyrene colloidal crystals as templates. EDS and SEM showed a face‐centered cubic (FCC) structure TiO2 inverse opal was obtained. Glucose oxidase (GOx) was successfully immobilized on the surface of indium‐tin oxide (ITO) electrode modified by TiO2 inverse opal (TiO2(IO)). Electrochemical properties of GOx/TiO2(IO)/ITO electrode were characterized by using the three electrodes system. The result of cyclic voltammetry showed that a couple of stable and well‐defined redox peaks for the direct electron transfer of GOx in absence of glucose, and the redox peak height enhanced in presence of 0.1 μM glucose. Compare with the ordinary structured GOx/TiO2/ITO electrode, inverse opal structured GOx/TiO2(IO)/ITO electrode has a better respond to the glucose concentration change. Under optimized experimental conditions of solution pH 6.8 and detection potential at 0.30 V versus saturated calomel electrode (SCE), amperometric measurements were performed. The sensitivity and the detection limit of glucose detection was 151 μA cm−2 mM−1 and 0.02 μM at a signal‐to‐noise ratio of 3, respectively. The good response was due to the good biocompatibility of TiO2 and the large effective surface of the three‐dimensionally ordered macroporous structure.