Structurally Stable Bilayer Hydrogel Interfaces Enabling High-Fidelity Electrophysiological Signal Monitoring under Harsh Mechanical Environments

Epidermal electrodes are essential for long-term and high-fidelity electrophysiological monitoring but often fail to maintain structural integrity during daily routines, especially under extreme mechanical disturbance. Herein, we engineer a mechanically resilient and conductive bilayer hydrogel (BLH) electrode based on rapid in situ gelation (94 s) to achieve robust topological integration with a rigid bacterial cellulose (BC) stress carrier. The oxide layer of the uniformed liquid metal droplets continuously releases •O^-, catalyzing the abstraction of hydrogen atoms from monomers to generate free radicals, thus facilitating the rapid in situ polymerization and stable interfacial coupling of heterogeneous bilayer hydrogel design. Finite element analysis further substantiates that this architecture relies on the stress-prioritized dispersion within the high-modulus stress carrier that efficiently mitigates structural degradation and electrochemical performance deterioration induced by external stress concentration. Consequently, the BLH electrode exhibits robust mechanical properties and sustained durability, maintaining stable performance after 50,000 bending cycles and 3000 impacts, collectively enabling reliable long-term signal acquisition (SNR, ∼16.1 dB) in complex motion scenarios. This ingenious architectural strategy holds great promise, offering a transformative perspective for developing highly integrated and mechanically stable hydrogel electrodes in high-fidelity signal acquisition under complex mechanics.