An Injectable Electroactive Hydrogel Engineered for Stable Bioelectronic Interfaces

Electroceutical therapies are fundamentally limited by the electrode–tissue interface: achieving long‐term, low‐impedance electrical coupling while maintaining mechanical compliance, and intimate tissue contact in wet environments. Minimally invasive deployment remains a persistent challenge. Injectable conductive hydrogels provide a promising strategy by enabling in situ formation of soft, conformal, and bioactive interfaces within complex and irregular tissues. Here we present an injectable, wet‐adhesive, and electroconductive hydrogel platform composed of catechol‐modified hyaluronic acid, alginate, and edge‐functionalized graphene (EFG). The pre gel display pronounced shear‐thinning and rapid self‐recovery, supporting catheter‐compatible delivery and spatial localization after injection. A dual ionic and oxidative crosslinking mechanism decouples gelation kinetics from bulk mechanical properties and tissue‐gel interfacial adhesion, yielding a tissue‐matched interface that resists delamination under physiological conditions. Incorporation of EFG adds electrical conductivity and charge injection capacity, providing electrochemical functionality relevant to stimulation. The hydrogel maintains stable mechanical and conductive performance and supports the viability of human neural cells in vitro. Ex vivo studies in porcine brain tissue demonstrate intimate conformity and integration, while four‐month subcutaneous implantation in sheep confirms favorable in vivo biocompatibility without adverse inflammatory responses. Collectively, this work establishes an injectable conductive hydrogel platform for stable, flexible, and electrochemically active bioelectronic interfaces.