In this paper, a novel silicon-based light-addressable potentiometric sensor (LAPS) has been designed for the detection of 1,5-anhydroglucitol (1,5-AG) in human serum. Reduced graphene oxide-chitosan-ferrocene (RGO-CS-Fc)/AuNPs nanohybrids and pyranose oxidase (PROD) enzyme is used to fabricate biological sensitive membrane unit by layer-by-layer assembly technology. When a bias voltage is provided to the LAPS system, the catalytic oxidation reaction between 1,5-AG and PROD to produce H2O2. The by-product H2O2 can oxidize Fc(Fe2+) ions in RGO-CS-Fc nanohybrids into Fc(Fe3+) ions, which cause the potential of the sensitive membrane surface to change and the potential shift of I-V curve will generate a corresponding offset response. Under the optimal conditions, the potential shift of the LAPS is linearly related to the concentration of 1,5-AG at 10 µg·mL-1 -350 µg·mL-1 with the correlation coefficient of 0.97414. The sensitivity is 0.44273 mV/µg·mL-1 and the lowest detection limit is 10 µg·mL-1. In addition, the biosensor showed good specificity, acceptable stability and satisfactory recovery rates (91.28%-107.66%), which would be a potential testing methods in actual clinical samples.
Keywords: 1,5-anhydroglucitol; Gold nanoparticles; Light-addressable potentiometric sensor; Pyranose oxidase; Reduced graphene oxide-chitosan-ferrocene nanohybrids.
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