Bioinspired Epidermal Electrode With Excellent Environmental Tolerance and Adhesion for Robust Electrophysiological Monitoring.

Flexible epidermal electrodes often suffer from performance degradation under harsh conditions, such as high humidity, low temperature, and accelerated aging. Drawing inspiration from the bicontinuous structure of coral reef exoskeletons, we developed a bio-mimetic conformal dry electrode (CGAg@PUA) that integrates a highly conductive skeleton with an adhesive matrix. Gravity-driven self-deposition of silver nanoparticles (AgNPs) on the lower electrode surface creates planar bicontinuous conductive paths. The PUA matrix, featuring polydimethylsiloxane soft segments, offers superior elasticity, adhesion, and low-temperature resistance. Additionally, carbon nanofibers (CNFs) and graphene (GR) dispersed in the matrix establish continuous 3D conductive pathways. CGAg@PUA exhibited excellent cytocompatibility and biological safety in cytotoxicity assessments. After 24 h of accelerated aging, the CGAg@PUA-20 electrode retained 57.3 ± 6.3% of its initial adhesion strength and 75.5 ± 4.8% of its tensile strength on non-degreased porcine skin. The in situ adhesion strength on non-degreased porcine skin reached 566.2 ± 32.4 kPa at -80°C. At 10 Hz, the skin interface impedance of the CGAg@PUA-20 electrode was 91.4 ± 5.2 kΩ·cm2, while after immersion in deionized water for 24 h, the impedance decreased by 6%. At last, the CGAg@PUA electrode demonstrates stable, prolonged capability to acquire high-quality electrocardiogram (ECG), electromyography (EMG), and electroencephalogram (EEG) signals.