Underwater Instant Adhesive Hydrogel Interfaces for Robust Biosensing on Diverse Species

Abstract Hydrogel‐assisted soft biosensors have emerged as transformative platforms for multimodal physiological monitoring in amphibious environments. However, developing instant underwater adhesive, scalable manufacturing, and robust interfaces for long‐term continuous multi‐physiological bioelectronics remains challenging. Here, a universal and facile fabrication strategy is presented that overcomes these limitations through molecular entanglement engineering to fabricate instant underwater adhesion hydrogel interfaces, exhibiting rapid, strong interfacial toughness over 230 J•m −2 within 10 s. Besides, a roll‐to‐roll scalable manufacturing protocol for practical transformation is established. The hydrogel interfaces with tissue‐like softness ≈109 kPa, enabling seamless multimodal biosensor integration across interfaces from aquatic organisms to amphibious species and human epidermis for reusable and long‐term usage, facilitating simultaneous multiparametric physiological signal acquisition and behavioral tracking. These findings establish a new design framework of molecular entanglement engineering for instant adhesive hydrogel interfaces, which enables reliable and rapid response biosensing technologies for healthcare monitoring and wildlife conservation.