A novel electrochemical non-enzymatic glucose sensor based on Au nanoparticle-modified indium tin oxide electrode and boronate affinity

Abstract

In this article, a sandwich-type electrochemical sensor for selective determination of glucose based on the formation of glucose-boronic bidentate complex has been developed. 3-aminophenylboronic acid (m-APBA) was immobilized on the gold nanoparticles modified ITO electrode with the linker molecule 4-mercaptobenzoic acid (p-MBA). Then, glucose was captured by boronic acid group from m-APBA as the primary receptor and further grafted with an electroactive ferroceneboronic acid (FcBA) as the secondary receptor to form the sandwich-type sensor for selective detection of glucose. For comprehensively understanding the effect of the charge and structure of the terminal boronic acid group of 3-APBA on its binding to glucose, surface pKa was studied by electrochemical titration method, and it was proved the feasibility of examining glucose in physiological condition by the sandwich-type electrochemical sensor. The electrochemical characteristics of the as-prepared sensor were investigated by using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The electrochemical sensor displayed a linear detection range of glucose from 0.5 mmol L−1 to 30 mmol L−1, with detection limit of 43 µmol L−1. The sensor exhibited good performance in selectivity study with the coexistence of galactose, fructose, mannose and other common interferences in physiological environment, such as, uric acid, ascorbic acid and dopamine. The as-prepared electrode with high sensitivity, good stability and reproducibility as well as excellent biocompatibility made it promising for the development of enzyme-free sensors.