In Situ Bulk and Interfacial Interlocking-Induced Highly Dynamically Entangled Hydrogel of Myocardium-Matching Mechanics, Electrophysiological Functions, and Robust Tissue Adhesion for Cardiac Repair

Myocardial infarction (MI)-induced heart failure is challenging because of poor cardiac self-repair and adverse remodeling. Hydrogel-based cardiac patches require integrated mechanical, electrical, adhesive, biocompatible, and biodegradable properties that remain difficult to achieve. Here, we report that a polysaccharide-based hydrogel patch, i-HEBioPEC, is realized by deliberately further dynamically interlocking an already highly entangled biopolyelectrolyte complex (HE-BioPEC) hydrogel network in situ via a chitosan and EDC/NHS coupling, respectively, inducing a physical bridging and chemical cross-linking synergistic interlocking mechanism. The patch enables on-demand cardiac repair through in situ tissue interlocking, exhibiting myocardium-like strain-stiffening, high toughness, fatigue resistance, tunable strength, and excellent biocompatibility, antimicrobial, and hemostatic performance. In MI rats, i-HEBioPEC effectively suppressed left ventricular dilation and adverse remodeling, improving the cardiac function. Notably, treated rats developed thinner, more mature scars with better functional recovery, indicating the active guidance of favorable repair. This work provides a new design strategy for multifunctional cardiac patches.