At the heart of the discovery is the Integrated Organ and Printing System (ITOP), which is unlike any 3D printer we've seen so far. It uses "biodegradable, plastic-like material" to form the shape of tissues, as well as water-based ink to hold cells and a series of microchannels to allow oxygen and nutrients to flow through. The idea is to make strong tissue that effectively integrates into animals and humans.

Sure, we've been hearing about 3D printed organs for years, but this announcement is notable for several reasons. Atala's team used the ITOP to print human-sized ears that were implanted under the skin of mice and, over the course of two months, managed to form cartilage and blood vessels. They've also seen similar progress when implanting muscle tissue and skull bone in rats. At this rate, it might not be too long before we start seeing human trials.