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 (B 4 C) 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 B 4 C 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 ─NH 2 /─OH groups, eliminating the need for additional chemical modifications. The resulting B 4 C‐ACT@GOx electrode exhibits high sensitivity (36.288 µA mM −1 cm −2 ) within the physiological sweat glucose ranges (5 µM–1 m M ), 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.