Swiss researchers have come a step closer to building to a better artificial heart. It’s a squishy prototype that’s 3D-printed from silicone. This soft artificial heart also has a chamber that fills up and deflates, mimicking the muscle contractions of a human heart. Traditional artificial hearts are made from plastic and metal, which the human body can reject. The 3D-printing method would also allow doctors to customize the size and fit of each soft artificial heart to the patient. The heart is still a work in progress. It beats for about 30 minutes or about 3,000 beats before the silicone breaks down. The next step is for researchers to improve the material and design. Watch our video to see how the heart works.