Israeli researchers have printed a 3D heart using a patient’s own cells, something they say could be used to patch diseased hearts — and possibly, full transplants.

The heart the Tel Aviv University team printed in about three hours is too small for humans — about 2.5 centimeters, or the size of a rabbit’s heart. But it’s the first to be printed with all blood vessels, ventricles and chambers, using an ink made from the patient’s own biological materials.