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

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 H 2 O 2 . The H 2 O 2 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 (R 2 =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.