The heart cannot regenerate new tissue, because cardiomyocytes, or heart muscle cells, do not divide after birth. However, researchers have now developed a shape memory polymer to grow cardiomyocytes. Raising the material’s temperature turned the polymer’s flat surface into nanowrinkles, which promoted cardiomyocyte alignment. The research is part of the growing field of mechanobiology, which investigates how physical forces between cells and changes in their mechanical properties contribute to development, cell differentiation, physiology, and disease.