Hybrid nanostructured ZnO–CeO2/rGO electrochemical biosensor for enhanced non-enzymatic sweat glucose detection

Many electrochemical glucose sensors rely on enzymatic catalysts such as glucose oxidase (GOx). However, such enzyme-based sensors are susceptible to environmental perturbations, which can compromise sensitivity and measurement reproducibility. Here, we report a flexible, enzyme-free sweat-glucose sensor for wearable diagnostic systems by co-depositing hydrothermally prepared zinc oxide–cerium oxide/reduced graphene oxide (ZnO–CeO 2 /rGO) nanocomposites onto laser-scribed graphene electrodes (LSGE) patterned on polyimide (PI) films. Scanning electron microscope (SEM), X-ray diffraction (XRD), UV–vis spectroscopy, and Raman spectroscopy verified the formation and structural integrity of the hybrid nanocomposite. The electrochemical characterization, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), indicated accelerated charge transfer after modification. Under optimized conditions, the biosensor quantified sweat glucose over 0.01–3.0 mM with a sensitivity of 32.5 μA·mM −1  cm −2 and a low detection limit of 14 μM. Proof-of-concept measurements on volunteers before and after meals further supported its feasibility for wearable and personalized healthcare diagnostics.