The Application of Injectable Hydrogels in Myocardial Infarction Repair: Material Design, Biological Functions and Clinical Translation.

Myocardial infarction remains a major clinical challenge because ischemic injury triggers inflammation, oxidative stress, cardiomyocyte loss, impaired vascularization, and adverse ventricular remodeling. Injectable hydrogels offer a minimally invasive and versatile strategy for post-infarction cardiac repair by providing structural support, localized bioactive delivery, and dynamic modulation of the injured myocardial microenvironment. This review highlights pathology-informed design principles for injectable hydrogels, including shear-thinning injectability, in situ gelation, tissue adhesion, modulus matching, fatigue resistance, biodegradability, and controlled bioactivity. We further discuss hydrogel-based strategies for immunomodulation, angiogenesis, fibrosis attenuation, extracellular matrix remodeling, and myocardial regeneration. Finally, translational progress and key challenges involving biosafety, scalable manufacturing, standardization and long-term efficacy are examined. This review provides a concise framework for developing next-generation injectable hydrogels for myocardial infarction repair and clinical translation.