Heart disease is the leading cause of death in the U.S., and about 790,000 Americans experience heart attacks each year, according to the American Heart Association. But in a recently released paper led by the University of Minnesota, a group of biomedical engineering researchers revealed the creation of a 3-D-printed patch that can help heal the scar tissue that forms after a heart attack and which can impair long-term function.

The method uses laser-based 3-D-bioprinting to print adult human heart cells onto a small cell matrix. Researchers tested the patch on a mouse after a simulated heart attack and found the mouse’s heart function increased after several weeks. Because the patch was made from organic proteins already found in the heart, after time it absorbed into the body and did not require follow-up surgery. The researchers have filed a patent on the technology and are already working on developing a larger patch that could eventually be used to heal a human heart.