Microspheres in myocardial infarction therapy.

Myocardial infarction (MI) remains a leading cause of heart failure. Although contemporary interventions improve early survival, they fail to promote cardiac repair or prevent long-term adverse remodeling. Microspheres, with injectability, high surface-to-volume ratio, and tunable structure, have emerged as versatile therapeutic platforms and have been clinically applied in chemotherapy, hemostasis, and long-acting injectable formulations. In MI therapy, microspheres can encapsulate diverse bioactive agents, modulate the infarct microenvironment in a minimally invasive manner, and promote cardiac repair. This review introduces microsphere morphology, size, materials, and major fabrication techniques, including emulsion-solvent evaporation, spray drying, electrospraying, and microfluidics. It also summarizes preclinical evidence on delivery routes, intramyocardial, epicardial, and intracoronary, and emphasizes design strategies. Furthermore, the use of microspheres for bioactive-agent delivery, cell therapy, and three-dimensional engineered cardiac tissues is reviewed. Finally, the limitations and future perspectives of microsphere-based therapy for MI are discussed, aiming to inspire innovative strategies and accelerate clinical translation.