On-Off Ratiometric Electrochemical Biosensor for Accurate Detection of Glucose

Abstract

A highly selective and accurate on-off ratiometric electrochemical biosensor to detect glucose was proposed based on gold nanoparticles (AuNPs)-glucose oxidase (GOD) nanocomposites as the catalyst for both the oxidation of glucose and the electrochemical reduction of O2 and the thionine as the inner reference signal for the first time. The reduction peak of O2 catalyzed by AuNPs-GOD at −0.45V decreased in GOD-glucose reaction in which the O2 was consumed gradually to produce H2O2. While, the reduction peak of the produced H2O2 catalyzed by thionine at −0.24V increased gradually. By using the ratiometric peak current as detection signal, a novel on-off ratiometric electrochemical biosensor for glucose detection was developed and exhibited an acceptable detection limit of 11.66μM and a wide linear range from 35.43μM to 15mM. The biosensor also exhibited high accuracy, high selectivity, good reproducibility and high sensitivity. The ratiometric electrochemical approach not only developed a new method for highly selective and accurate detection of glucose but also provided a good idea for accurate and selective analysis of other analytes.