Just when we’ve wrapped our minds around 3-D printing, researchers introduce a concept that’s even more fantastical: bioprinting.

For the last few years, 3-D printing has been making headlines in many areas including art, engineering and manufacturing because it allows people to print digital designs as three-dimensional objects using materials such as plastic, ceramic or metal.

It didn’t take long for the medical community to ask: Could you also print human tissue? The answer is, seemingly, yes. It starts when scientists take human cells gleaned from biopsies or stem cells and feed them into a special bioprinter that deposits the cells in the right arrangement. These cells, called bio-ink, are alive and need to be fed. They’re given a nutrient-rich gelatin to sustain them. After becoming embedded in this microgel, the cells begin to fuse and organize themselves into a collective system.

So far, simple organs, bits of bone and structures such as ears and tracheas have been printed. Researchers hope to one day print replacement organs for people needing transplants. However, much more work needs to be done before made-to-order organs become reality. One hurdle is finding a way to bioprint the intricate blood-vessel networks that replenish organs with oxygen and nutrients.

The possibilities for bioprinting go beyond transplant-ready organs — from doing pharmaceutical testing on 3-D printed tissues and printing skin grafts for burn victims to building insulin-producing pancreatic tissues that help manage diabetes and providing medical students with practice models of organs. The potential benefits of bioprinting are innumerable.

While bioprinting may sound like science fiction, it might not be long before it starts to make an impact on medical science. Ready, set, print.