An Injectable “Gas-Electro” Bionic Hydrogel for Spatiotemporal Monitoring and Repair of Myocardial Infarction via Sustained H ₂ S Release and Electrophysiological Repair

Myocardial infarction (MI) is a leading global cause of death, marked by oxidative stress, electrical dysfunction, and cardiomyocyte loss. Current treatments often cannot simultaneously regulate the pathological microenvironment and restore electrical integrity. Here, we report an injectable "gas-electro" bionic hydrogel (POPHM) for spatiotemporal monitoring and repair of MI. POPHM integrates a dynamic PVA/PEI-PBA/ODex network for mechanical stability and injectability, sustained H₂S release via a MeAC-PEG donor for anti-inflammatory, antioxidative, and pro-angiogenic effects, and TEMPO-CNF-modified MXene nanosheets as conductive fillers to form a biomimetic electrical network. The hydrogel shows good biocompatibility, suitable elasticity, and conductivity (1.44 mS·cm^-1) matching native myocardium. In vitro, it enables real-time high-fidelity electrophysiological monitoring (e.g., ST-segment elevation) and enhances H9C2 viability and connexin 43 expression. In rat MI models, POPHM reduces infarct size, attenuates fibrosis and inflammation, promotes angiogenesis, and improves cardiac function (EF from 24% to 53.05%). Transcriptomics reveals activated pathways in energy metabolism, antioxidant defense, and cardiac development. By combining H₂S gas therapy, MXene-mediated electrical restoration, and real-time ECG monitoring, this theranostic platform offers a promising strategy for comprehensive MI management.