Laser‐Etching Induced Differential Internal Stress Design in PEDOT:PSS Hydrogels for Self‐Curling Flexible Bioelectronic Interfaces

Abstract Flexible electrodes can conformably adhere to tissues, reducing mechanical mismatch compared with rigid metal electrodes. However, they still require complex surgical placement, which brings a high risk of tissue injury. Here, laser‐etching PEDOT: PSS (LP) hydrogels with an alternating rigid‐soft grooved structure are developed, exhibiting tunable self‐curling performance through the regulation of differential internal stress. Inspired by the laser attenuation, distinct phase separation, conformational transition, and crystallinity distribution are engineered in the out‐of‐plane direction of LP hydrogels. These modifications drive the release of differential internal stress, triggering the spontaneous 2D‐to‐3D curling transformation in wet environments. By designing laser scanning paths in the in‐plane direction, diverse complex flexible interfaces are obtained for matching variously shaped tissues. The hydration‐triggered self‐curling property enables LP hydrogels to autonomously conform to targeted tissues without adhesive layers or sutures, thereby simplifying implantation and enhancing electrode‐tissue compliance. Rat models demonstrate that the self‐curling LP hydrogels maintain high‐fidelity nerve and cardiac signal recording or/and modulation capabilities. This study offers an easy‐to‐use self‐curling flexible electrode interface for compatibility recording and modulating electrophysiological signals in diverse, complex tissues.