Investigation of Graphene Oxide/Mesoporous Silica Supports for Enhanced Electrochemical Stability of Enzymatic Electrodes

Abstract

Mesoporous silica materials (MSMs) are widely used materials in many applications due to their diverse pore structures. However, the electrical conductivity of MSMs is poor which limits their use in electrochemical applications. In this study, widely used MSMs of different structural properties such as MCM-41, MCM-48, SBA-15, and SBA-16 were synthesized and reinforced with graphene oxide (GO) to obtain conductive composite supports for enzyme immobilization. MSMs were first synthesized using a hydrothermal method and characterized by Fourier-transform infrared spectroscopy, X-ray crystallography, scanning electron microscopy/energy dispersive X-ray, and MAPPING techniques. Aqueous dispersion of GO:MSM composites were prepared with as-synthesized materials and coated on screen-printed electrodes (SPE). The best composites were chosen based on their electroanalytical performance. Glucose oxidase (GOx) was then immobilized on modified SPEs using a simple drop-casting method to produce enzymatic electrodes. The electroanalytical performance of the enzymatic electrodes was investigated using different glucose concentrations to demonstrate biocatalytic activity. Stability tests were performed using intraday and interday measurements which revealed that SPE/GO:MCM-41/GOx electrode showed a more stable performance (3-folds) than SPE/GO/GOx electrode. This study presents an investigation of MSM mixed with GO in enzymatic electrochemical systems providing insight into the use of such materials to preserve enzyme activity.