Self-Powered Glucose Sensing with Cu-BDC/rGO Heterostructure: Ultra-Selective, Highly Sensitive, and IoT-Enabled Real-Time Monitoring

The advancement of flexible, wearable glucose sensors has significantly improved continuous glucose monitoring systems. However, their long-term, uninterrupted operation requires integrated self-powered functionality. In this work, we present a multifunctional nanocomposite - Cu-BDC/rGO - synthesized by combining a copper-based metal-organic framework (Cu-BDC) with reduced graphene oxide (rGO). The Cu-BDC contributes a high surface area, abundant active sites, and intrinsic electrocatalytic activity, while rGO imparts excellent electrical conductivity and mechanical flexibility. Together, these synergistic properties of Cu-BDC and rGO enable superior nonenzymatic glucose sensing performance, achieving a remarkable sensitivity of 7379.8 μA mM^-1 cm^-2 and a low detection limit of 0.49 μM. Beyond sensing, the nanocomposite also delivers excellent supercapacitive behavior, exhibiting a specific capacitance of 336 F g^-1 at 1 A g^-1 and retaining 80.42% of its capacitance after 2000 cycles with 90.7% Coulombic efficiency. To demonstrate practical utility, a proof-of-concept self-powered wearable device was developed using the Cu-BDC/rGO composite, capable of real-time sweat glucose monitoring directly from glucose oxidation without external batteries. Further demonstration of real-time wireless data transmission to a mobile device was performed, establishing its remote applicability in continuous healthcare monitoring. This study highlights the potential of multifunctionality of Cu-BDC/rGO nanostructures in enabling next-generation biosensing platforms that seamlessly integrate energy harvesting, storage, and sensing capabilities, paving the way for autonomous, IoT-enabled, personalized digital healthcare systems.