Photo taken on April 15, 2019 shows a 3D-printed heart with human tissue at the University of Tel Aviv in Israel. Tel Aviv University scientists said on Monday that they have printed the first 3D heart, by using patient's cells and materials. The heart, which was produced in a lab, completely matches the biological characteristics of the patient's heart. It took about three hours to print the whole heart. (Xinhua/JINI/Gideon Markowicz)