Human organ transplants offer a crucial lifeline to people with serious illnesses, but there are too few organs to go around: in the U.S. alone, there are more than 112,000 people currently waiting for transplants. The promise of 3D printing organs is one possible solution to address this shortage but has been fraught with complexity and technical barriers, limiting the type of organs that can be printed. Researchers are now pushing through these barriers by leveraging a decades-old technique to reproduce any tissue type.