Chen et al. (2020) used injectable thermosensitive hydrogels carrying colchicine, for repair after MI, while Chow et al. (2017) used PEG hydrogel to deliver erythropoietin (EPO) and cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) to the infarcted myocardium, thereby promoting myocardial repair. Here, EPO is linked to myocardial infarction.