Myocardial infarction (MI) is a disease in which the coronary artery supplying blood to the heart is narrowed or blocked, causing irreversible damage to the myocardium. Recently, the transplantation of stem cells to the damaged region was found to enhance the regeneration of damaged heart tissue. However, the low engraftment rate of stem cells on a dynamically beating heart has become a major obstacle.
 Professor Dong Sung Kim (Department of Mechanical Engineering) and Dr. Andrew Choi succeeded in transplanting in vivo priming bone marrow mesenchymal stem cell (BMSC) sheet based on thermoresponsive nanofiber membrane through joint research with the College of Medicine, the Catholic University of Korea, and the City University of Hong Kong. The transplantation of BMSCs in a “sheet” form greatly increased the engraftment rate of stem cells; and furthermore, the transplantation of a BMSC sheet with a human umbilical vein endothelial cell (HUVEC) sheet dramatically improved the angiogenesis of damaged heart tissue and promoted cardiac repair.
 Though the efforts to treat MI with diverse bio-products continue, the constant pulsing and highly curved nature of the heart have hindered the efficient regeneration of heart tissue. The research team created a highly integrable in vivo priming BMSC sheet which securely preserves the pluripotent/self-renewal potential of stem cells and specializes the vascular regeneration. This comprehensive study provides strong evidence that in vivo priming of an aligned BMSC sheet with an aligned HUVEC sheet develops the therapeutic potential for cardiac repair.
 This approach solved the poor integration and low engraftment rate, which have been the main challenges of the cardiac patch and is evaluated to have suggested a new concept of the patch by improving heart function for MI treatment. The research, which was published in one of the prestigious journals in biomaterials, Biofabrication, was supported by the National Research Foundation of Korea (NRF) and Tung Biomedical Sciences Centre.