High-performance ZnO:CuO composite-based fiber-shaped electrode for non-enzymatic glucose sensing in biological fluids

The growing diabetes epidemic necessitates new glucose sensors, as traditional enzyme-based and planar electrodes face limitations in environmental stability and seamless integration into wearable technology. This research tackles these issues by designing a flexible, enzyme-free glucose sensor utilizing a co-deposited ZnO:CuO (CZ) composite on PET monofilament. This approach improves the tensile strength (55 mm at 2.7 kg.f) and electrical conductance (0.32 S), of the Ni-coated PET fiber, resulting in a strong and reliable sensing platform. The electrode's enlarged electrochemical surface area (0.11 cm²), offer a high density of active sites for glucose interaction, and the synergistic interface significantly enhances both ion and charge mobility. This results in exceptional sensitivity (35.05 mA.cm⁻².mM⁻¹), a rapid response (24 s), and a low detection limit (0.15 mM). Durability tests demonstrate that the sensor retains 80% of its sensitivity after 500 bending cycles, making it well-suited for wearable applications. Furthermore, the sensor accurately detects glucose in biological samples, such as saliva, highlighting its potential for non-invasive, real-time glucose monitoring in wearable healthcare systems.