Achieving high-performance epidermal electrodes for long-term electrophysiological monitoring remains a significant challenge, as it necessitates a delicate balance between high electrical conductivity, optical transparency, mechanical compliance, and environmental stability within a single platform. Herein, we present a multifunctional epidermal bioelectrode (silk/Ag@Au BioE) fabricated by combining a silver-gold core-sheath nanowire (Ag@Au NW) network with a silk fibroin (SF) substrate via direct ink writing and solution-casting transfer techniques. The resulting electrode exhibits superior optical transmittance (up to 94.3%) and a low sheet resistance of 10.9 Ω/sq. A unique hydration-induced plasticization is employed to transform the initially rigid SF film into an ultra-soft, conformal skin interface. This process induces the spontaneous formation of micro-wrinkled architectures, which, in synergy with a meticulously designed second-order serpentine mesh, imparts exceptional omnidirectional stretchability and robust mechanical durability. The electrode also demonstrates high breathability (1591 g/(m²·day)), excellent resistance to sweat and oxidation, and sustainable reusability over multiple hydration-dehydration cycles. This integrated design enables high-fidelity, long-term monitoring of electrocardiogram (ECG), electromyogram (EMG), and electrooculogram (EOG) signals under dynamic and harsh conditions, substantially outperforming conventional Ag/AgCl electrodes. This work provides a versatile and robust material platform for next-generation wearable healthcare diagnostics.

Stretchable and transparent electrodes (STEs) based on silver nanowires (AgNWs) have garnered considerable attention due to their unique optoelectronic features. However, the low oxidation resistance of AgNWs severely limits the reliability and durability of devices based on such STEs. The present work reports a type of core-sheath silver@gold nanowires (Ag@Au NWs) with a morphology resembling dual-headed matchsticks and an average Au sheath thickness of 2.5 nm. By starting with such Ag@Au NWs, STEs with an optical transmittance of 78.7%, a haze of 13.0%, a sheet resistance of 13.5 Ω·sq.⁻¹, and a maximum tensile strain of 240% can be formed with the aid of capillary-force-induced welding. The resultant STEs exhibit exceptional oxidation resistance, high-temperature resistance, and chemical/electrochemical stability owing to the conformal and dense Au sheath. Furthermore, non-enzymatic glucose biosensors are fabricated employing the Ag@Au NW STEs. The electrocatalytic oxidation currents are proportional to glucose concentrations with a high sensitivity of 967 μA·mM⁻¹·cm⁻² and a detection limit of 125 μM over a detection range of 0.6 to 16 mM. Additionally, the biosensors demonstrate an appealing robustness and anti-interference characteristics, high repeatability, and great stability that make them adequate for practical use.