Organ failure is a tragedy that claims thousands of lives every year. When a heart gives out, it’s especially devastating — we only have one, after all. On top of this, the list of heart donors is thin and demand is high, with health hearts costing a large sum of money. To get around this and potentially save more lives, a group of scientists is working on developing artificial human hearts using 3D printers. They’re made of the same stuff as your heart, but the way they’re made will shock you.