Tissue-AdaptableHydrogel for Mechanically CompliantBioelectronic Interfaces

A hydrogel with tissue-like softness and ideal biocompatibility has emerged as a promising candidate for bioelectronics, especially in bidirectional bioelectrical transduction and communication. Conformal standardized hydrogel biointerfaces are in urgent demand to bridge electronic devices and irregular tissue surfaces. Herein, we presented a shape-adaptative electroactive hydrogel with tissue-adapted conductivity (≈1.03 S/m) by precisely regulating molecular chains and polymer networks of multisource gelatin at the molecular scale. Local amine-carboxylate electrostatic domains formed by ion interactions between gelatin and sodium citrate significantly enhance the physiological adaptability and regulate the biodegradation period. Benefiting from the reversible fluid-gel transition property, the hydrogel can be <i>in situ</i> gelatinized and establish a dynamic compliance bioelectronic interface with tissues by chemical bonding and the physical topological effect. Further, the mechanical-electrical coupling capacity of the hydrogel interface allows for bioelectrical conduction function reconstruction and electrical stimulation therapy after mechanical bridging at tissue defects to boost tissue regeneration and sensory restoration.