Mediator enhanced glucose detection using organic–inorganic hybrid supramolecular assembly on gold electrodes

Abstract

In this study, a new organic–inorganic material, based on an alpha-metatungstate [H2W12O40]6− cluster, was synthesized via the hydrothermal method by using aminopyridinium (APy)+ cations as the hybrid material, and characterized by FT-IR and UV spectra analysis. The hybrid composite was immobilized on a gold electrode decorated with gold nanoparticles (AuNPs) and the modified electrode exhibited excellent electrocatalytic activities towards the reduction of H2O2 at neutral pH with a response time of <10s. The H2O2 response at the modified electrode displays a linear response ranging from 40μM to 10mM.Based on the H2O2 reduction activity, the (APy)6[H2W12O40] composite was successfully used for the fabrication of a novel enzymatic glucose biosensor. The glucose oxidase enzyme (GOx) was immobilized onto the hybrid composite on AuNPs/gold electrodes; the (APy)6[H2W12O40] composites were used as both mediation and bridging molecules. A multilayer architecture was constructed from hybrid POM alternating with (GOx), using glutaraldehyde as a covalent attachment cross-linker. Cyclic voltammetry (CV), SWV and chronoamperometry were used to determine the electrochemical properties of the mediator and characterize its reaction with (GOx). The resulting glucose biosensor exhibits a wide linear response for glucose from 40μM to 10mM with a sensitivity of 15.0μAmM−1.