CuO-embedded laser-induced graphene microfluidic system for continuous, non-invasive, and cost-effective glucose monitoring in sweat

Abstract

This study presents a low-cost, high-sensitivity glucose sensor (COL-MC) fabricated by integrating CuO-functionalized laser-induced graphene (LIG) with a capillary-driven microfluidic chip. The novel two-step synthesis eliminates noble metals, enhancing affordability while achieving a large surface area for superior sensitivity. The sensor demonstrates a linear response (R² > 0.996) across 0.1–1.5 mmol/L glucose concentrations in sweat, with rapid detection (600 ms response time) and ultra-low detection limit (80 μmol/L, ΔI = 12.5 μA). The integrated microfluidic system employs capillary valves and serpentine channels to enable sequential fluid collection and continuous monitoring without external equipment. This wearable platform maintains stable performance for one week, advancing non-invasive health diagnostics through enzymatic-sensor-level sensitivity and scalable manufacturing. Its successful sweat glucose detection showcases significant potential for sports monitoring, personalized healthcare, and chronic disease management, representing a critical step toward practical wearable biochemical sensing technologies.