Sweat-Enhanced Self-Adhesive Double-Network Hydrogel for Dynamic Skin Electrophysiology
Huarun Liang, Mengjia Zhu, Shuo Li, Haomin Wang, Donghang Li, Xiaoping Liang, Haojie Lü, Xun‐En Wu, Haoxuan Ma, Nan Liu, Yingying Zhang
Abstract
Electrophysiological monitoring is essential in healthcare and life sciences, yet conventional Ag/AgCl electrodes face challenges such as interfacial instability and motion artifacts. Herein, we propose a sweat-enhanced electrode design with a double-network hydrogel, comprising Ca 2+ -modified silk fibroin (SF) and poly(acrylic acid) grafted with N -hydroxysuccinimide ester (PAA-NHS). The obtained biocomposite, SF-PAA-NHS (BioSP), exhibits strong skin adhesion through covalent cross-linking and intermolecular forces, achieving an interfacial toughness of 411 J m –2 . Upon sweating, SF enhances adhesion by strengthening molecular mobility and mechanical interlocking, resulting in a nearly 23% increase in interfacial toughness. Additionally, sweat electrolytes boost BioSP’s ionic conductivity by about 45%, enhancing its electrophysiological monitoring capabilities. BioSP can also be combined with elastomers for excellent antidrying performance. Finally, high-fidelity and long-duration electrophysiological measurements validate the superior performance of the sweat-enhanced electrode, representing a significant advancement in skin electrode technology for reliable and durable monitoring on dynamic and sweaty tissue.