Scientists have developed a soluble microneedle patch that, when applied to a damaged heart, releases the cytokine IL-4 directly into the infarct bed. IL-4 activates macrophages, immune cells that switch into a healing phase and promote heart tissue regeneration instead of inflammation. This targeted approach improves communication between heart muscle and blood vessel cells, leading to better recovery after a heart attack. The patch was tested in rodent and pig models where it reduced scar extent, improved left ventricular function and increased overall survival of the animals compared to conventional administration of IL-4 into the bloodstream. The microneedle patch also eliminated the systemic risks associated with IL-4 injections. This treatment modality represents a promising minimally invasive method to promote cardiac recovery after MI[1].