Ion-Responsive Microneedles Delivering Subtype-Specific Mitochondrial Extracellular Vesicles from HEY1⁺...

The pathogenesis of myocardial ischemia-reperfusion (MI/R) injury is intricately linked to mitochondrial dysfunction occurring during both the ischemic and reperfusion phases. Through single-cell transcriptome analysis, we identified a subpopulation of HEY1-high expressing cardiomyocytes (HEY1⁺ CMs) characterized by superior mitochondrial homeostasis. To leverage this, we isolated P5CS-type or ATP5B-type functional mitochondria from a ΔΨ_m-high subpopulation, which was obtained via membrane potential sorting following dual overexpression in HEY1⁺ CMs, and subsequently encapsulated them within HEY1⁺ CM-derived exosomes to achieve stable, targeted delivery. We designed a responsive microneedle patch based on local copper/iron ion dynamics to enable the stage-specific release of these mitochondria within the ischemic or reperfusion microenvironments. In a Bama minipig MI/R model, this system significantly ameliorated cardiac function, reduced infarct size, and attenuated cardiomyocyte death. Mechanistically, the therapeutic strategy enhanced mitochondrial structural integrity and energy metabolic function. This study establishes a responsive, stage-specific mitochondrial delivery platform, offering a promising strategy for the precision treatment of ischemic heart disease.