Flexible and Enzyme-Free Graphene-PVDF-Au Electrode for Glucose Detection in Sweat

Sweat-based electrochemical Glucose sensors offer a convenient, painless, and non-invasive alternative to traditional finger-prick blood tests for diabetes monitoring. However, enzyme-based sensors are often limited by instability, stringent storage requirements, and high costs. In this study, we introduce a novel, cost-effective, flexible, and enzyme-free electrode for Glucose detection in sweat. The electrode is produced from a polymer nanocomposite film consists of polyvinylidene fluoride (PVDF) and graphene nanoplatelets (GNPs), further enhanced with a 50 nm gold (Au) layer deposited via sputter coating. Comprehensive characterization of the electrode was conducted by field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and cyclic voltammetry (CV). The results reveal a sensitivity of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$172 \mu \mathrm{A} \cdot \text{mM}^{-1} \cdot \text{cm}^{-2}$</tex> across a linear Glucose detection range of 0.01-10 mM. It also exhibits high selectivity for Glucose compared to other interferents, such as ascorbic acid (AA), uric acid (UA), and lactic acid (LA). Validation in simulated sweat confirms its efficacy in Glucose detection. These findings demonstrate the electrode's potential for Glucose detection in sweat without the use of enzymes, paving the way for the development of non-invasive diabetes monitoring technologies.