Self‐Growing Conductive Hydrogels Establish Volumetric Biointerfaces for Cardiac Conduction Restoration

ABSTRACT Restoring three‐dimensional electrical conduction in infarcted myocardium remains a critical challenge, as conventional conductive hydrogel patches largely remain surface‐confined and prevent electrical coupling of residual cardiomyocytes within fibrotic scars. Here, we present a self‐growing conductive volumetric interface (SCOVE) that transforms surface‐confined biointerfaces into tissue‐integrated, three‐dimensional conductive networks. SCOVE is delivered as an injectable hydrogel precursor containing the tissue‐permeable conductive monomer 3,4‐ethylenedioxythiophene‐acetic acid sodium salt (ETE), which rapidly infiltrates infarcted myocardium and undergoes endogenous glucose‐triggered oxidative polymerization to self‐grow a conductive polyETE network in situ. The resulting hydrogel gels within 1 min, reaches cardiac‐mimetic conductivity (∼1 S m − 1 ) within 45 min, and preserves native myocardial mechanics without inducing tissue stiffening. In a rat myocardial infarction model, SCOVE penetrates the infarct, reduces scar resistivity by 2.54‐fold compared with conventional 2D conductive patches, restores electrical coupling among residual cardiomyocytes, enhances Cx43 expression, and accelerates impulse propagation. By replacing static, surface‐confined conductive patches with self‐growing volumetric biointerfaces, this work establishes a generalizable strategy for reconstructing tissue electrophysiology and advancing bioelectronic therapies for myocardial infarction and other electrically dysfunctional tissues.