Two-Dimensional Ternary Nanocomposite-Decorated Cellulose Field Effect Transistor for Nonenzymatic Sweat Glucose Sensing

Wearable sensors are effective point-of-care (POC) diagnostic tools for the timely analysis of a patient’s disease status. The best way to achieve such biosensors is by developing a device for the noninvasive investigation of human sweat. However, the ultralow concentrations of biomarkers in sweat pose challenges to achieving high sensitivity. The remarkable qualities of flexible paper field effect transistors (PFETs), including their high modulation index, pliability, transducing capability, and quick reaction, make them potential candidates for wearable sensors. Our study presents a biodegradable, disposable, scalable, low-cost PFET device for nonenzymatic, wearable glucose sensing applications. In the sequence, we further discussed the functionalization of the channel, electrodes, and sensing methods. Here, the semiconducting silver (Ag) nanoparticle (NP)-decorated cuprous oxide (Cu₂O) dispersed on reduced graphene oxide (rGO) was synthesized by a rapid, cheaper microwave-assisted method. Material characterization techniques validate the nanocomposite (NC) formation, which is patterned as the transistor channel. Charge (cation/anion) generated due to the electrolytes (analyte) and NC interaction develops interface potential and electric double layer (EDL)/capacitance change that stimulates the channel conductivity. The faster electron and hole mobility, coupled with the superior selectivity of Ag–Cu₂O and the high conductivity of rGO, collectively contribute to excellent electrocatalytic activity for glucose oxidation. The fabricated PFET sensor could achieve a limit of detection (LOD) of 96 nM with high sensitivity and self-amplification effect. Real-time applications using artificial sweat introduced with a physiological range of sweat glucose concentrations (0.01–0.1 mM) yielded promising findings, indicating the potential use of inexpensive and sustainable PFETs for wearable glucose sensors.