On-Off Ratiometric Electrochemical Biosensor for Accurate Detection of Glucose

•A novel on-off ratiometric electrochemical biosensor was developed for glucose detection.•The AuNPs-GOD was used to catalyze the oxidation of glucose and the reduction of O2.•Thionine was used to catalyze the reduction of produced H2O2 as an inner reference signal.•The proposed on-off ratiometric electrochemical biosensor showed good performances.

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 −0.45 V 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 −0.24 V 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 11.66 μM and a wide linear range from 35.43 μM to 15 mM. 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.

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