Conformal and adhesive gel for stable electrophysiology on hairy animals without shaving

Non-invasive collection of weak electroneurographic signals is crucial for cognitive neuroscience. However, animal scalps are often covered by dense hair, which presents a substantial barrier in the scalp-electrode interface for accurate electrophysiological acquisition. Although scalp hair removal is common practice in clinical settings, it has detrimental effects on the test subjects and is infeasible in many non-clinical scenarios. Here we report a hair-adaptable and adhesion-tunable (HAAT) scalp-electrode interface that can accurately acquire electroneurographic signals from hairy skins of animal and human. By synthetically integrating dynamic covalent bonds and ionic conduction channels in the copolymer poly(sodium thioctate-co-sulfobetaine methacrylate), we implement the key functionalities of the HAAT interface including penetration of dense hair layers, strong conformal skin-electrode adhesion, on-demand painless detachment, and sensitive neuroelectric coupling. We achieve stable and precise electroneurographic signals acquisition from human, monkey and mouse's scalps with various hair densities. The accurate event-related potential monitored during monkey vision-attention tasks facilitates the study of monkey brain activity. These results demonstrate the HAAT interface as an outstanding platform for conducting non-invasive research on animal cognition.