Boron Carbide Nanoskeleton-Engineered Wearable Biosensor for Real-Time Sweat Glucose Monitoring

Wearable electrochemical glucose sensors face critical challenges in balancing enzyme stability, electron transfer efficiency, and mechanical durability. In this study, we present a flexible glucose-sensing patch based on a boron carbide (B₄C) nanoskeleton grown directly on activated cotton textiles (ACT) via programmable vapor-liquid-solid (VLS) synthesis. By precisely tuning nickel catalyst size, interparticle spacing, and B:Ni molar ratio, we engineered nest-like 3D B₄C nanowire networks that preserve the ACT substrate's inherent flexibility and hierarchical porosity. This architecture ensures continuous electron conduction and supports hydrogen-bond-driven immobilization of glucose oxidase (GOx) through in situ-generated ─NH₂/─OH groups, eliminating the need for additional chemical modifications. The resulting B₄C-ACT@GOx electrode exhibits high sensitivity (36.288 µA mM^-1 cm^-2) within the physiological sweat glucose ranges (5 µM-1 mM), an ultrafast response time of 0.1 s, and longterm stability over 4 weeks. Integrated into a wireless patch, the device enables real-time glucose monitoring in human sweat. This work bridges nanoscale material engineering and wearable biosensor functionality, providing a scalable platform for personalized healthcare applications.