Silicon-based field-effect glucose biosensor based on reduced graphene oxide-carboxymethyl chitosan-platinum nanocomposite material modified LAPS

Abstract

In this study, a label-free glucose (Glu) biosensor was designed by modifying reduced graphene oxide-carboxymethyl chitosan-platinum nanoparticles (RGO-CMCS-Pt NPs) on a silicon-based light-addressable potentiometric sensor (LAPS) based on the field effect tube principle. Under the bias voltage, a modulated light source is directed onto the semiconductor layer of the sensor, generating a weak photocurrent. Simultaneously, Glu is catalyzed by glucose oxidase (GOD) to produce gluconic acid and H2O2. The H2O2 further decomposes to facilitate electron transfer, disrupting the potential balance on the biosensor surface and causing changes in the photocurrent-bias voltage (I-V) curve. The voltage offset demonstrated a linear relationship with the Glu concentration ranging from 0.01 mg/mL to 4.0 mg/mL. The linear equation was △V= 19.17331 C+ 75.46574 (R2 =0.98831) with a high sensitivity of 19.17 mV*mL/mg and a low detection limit (LOD) of 0.01 mg/mL (S/N = 3). Furthermore, the Glu biosensor exhibited good specificity, reproducibility, and stability, the biosensor also realized the detection of glucose in human serum samples with a relative standard deviation ranging from 0.63% to 3.47%, and the results were consistent with the hospital's biochemical indicators, which demonstrated the potential application of the prepared biosensor in the clinical detection of Glu.