For years, printing a new ear, muscle, or jaw has been nothing but science fiction. That’s largely because “bio-printed” tissues haven’t been strong or large enough to implant into humans. Until now.

Over the past decade, researchers at Wake Forest Baptist Medical Center have developed a new printer they’re calling the Integrated Tissue and Organ Printing System. And according to research published Monday in the journal Nature Biotechnology, it’s already outputting 3D-printed organs, bones, and muscles.

Senior study author Dr. Anthony Atala, who directs the Institute for Regenerative Medicine at Wake Forest Baptist Medical Center made his wish for this kind of tech known back in a 2009 TED talk. “We really would like to use smart biomaterials that we can just take off the shelf and regenerate your organs,” Atala said.

Get Data Sheet, Fortune’s technology newsletter.

And he has just gotten one step closer to that dream, while helping to close a massive organ shortage gap. In the U.S. today, 121,460 people are on the waiting list for an organ transplant, with a new name added to the list every ten minutes, reports the U.S. Department of Health and Human Services. Every day, 22 people die while waiting.

Atala’s organ-printing system could help solve this problem. Based on a whole new kind of 3D printer technology, the system outputs an object with two different printing methods. The first is a harder plastic-like tissue-building material that shapes the body parts, while the second, a delicate water-based gel ink, holds tissue cells in place.

The printed body parts also come with a system of built-in channels, so nutrients and oxygen from the body can flow into the new tissue after it is implanted. This keeps the printed parts alive and helps them develop into working parts of the body.

HP Is Betting Big On 3D Printing:

Using the new printer, the team has printed a range of tissues: soft muscle, cartilage, and hard bones. “We can use the same strategy to create other types of tissues as well,” said Atala, pointing to the possibility that the printer could one day help manufacture complex organs like livers and hearts.

In animal tests, the parts matured into functional tissue, developing their own blood vessels. Researchers were able to keep a baby-sized ear implanted in a mouse alive for two months. During that time both cartilage tissue and blood vessels formed in the ear. Researchers also tested out a new human jaw that could be used for facial surgery. Five months after implantation in a rat, that jaw had formed bone tissue.

But the printed ears and jaws aren’t quite ready for people yet. Before they can be implanted in humans, the printed parts will need be monitored longer, to know how well they will perform in a body after years of wear. But if the technology continues to shape up, the future of organ donation could be as simple as hitting print.