Greatist News examines and explains the trends and studies making headlines in fitness, health, and happiness. Check out all the news here.

Lawrence Bonassar 3D printed a real, honest-to-goodness prosthetic ear: One made of living tissues that can theoretically graft onto a human head with the same flex and feel as the real thing.

Once the domain of tech labs and cute charms, 3D printing — the process of creating objects by “printing” successive layers of a structural material — had made massive gains in the medical field. Bonassar, an associate professor at Cornell University, focuses on regeneration and analysis of muscoskeletal tissues, a.k.a. regenerating “parts of the body.” He and his lab have successfully created a 3D printed ear which was grafted on to lab rats, but can these developments be applied to humans? Read on to find out why Bonassar believes so.

What’s the Deal?

The short version is that Bonassar created an ear from a 3D printer which could be used in humans in the near future. The long version is complicated, but also enormously cool. It turns out that an ear is a tricky thing to print — not just for its inner-workings, but for its consistency too.

The cartilage found in ears is uniquely flexible, but Bonassar and his lab at Cornell are working to create synthetic materials that make replacing ears — and other cartilage-based human parts — easier for everyone.

Replacing cartilage comes with a certain amount of trauma, since it generally has to be taken from another part of the body (like, say, the ribs). To create a synthetic ear, Bonassar is able to scan the head of a potential patient and use a 3D printer to build a precise and unique plastic mold. Unlike the objects found at Makers Fairs, Bonassar fills the molds with a combination of collagen, living cartilage cells, and other materials that promote growth. In effect, they are printing living tissue.

And about 15 minutes later, you have an ear.

Why It Matters

The prospect of printing replacement body parts and organs is huge. For the most part, 3D printing has been a way to quickly and cheaply prototype different projects. For example, it has become an expedient way for Kickstarter projects to demonstrate cool new ideas without having to spend hundreds to build a fully functioning prototype.

Bonassar’s project is a little different, however. Instead of prototyping, the technology is being used to create finished products, and instead of gizmos and gadgets, it’s being used to create real, organic materials. The impact goes well beyond simply replacing ears. The complexities of 3D printing cartilage can provide important lessons for creating even more complicated organs.

While it may sound a little like science-fiction, other labs have already started experimenting with printing fully-functioning organs such as hearts, livers, and kidneys. The impacts of something like this are nearly endless. It could radically improve the quantity and quality of replacement organs and reduce stress on organ donor programs, as well as ease the surgery itself by allowing doctors and scientists to create bespoke body parts tailored and sized for every individual.

Is It Legit?

Almost. Bonassar was able to create a prosthetic human ear, but so far it has only been tested on rats. In tests, published in PLoS One, synthetic ears grafted onto rats kept their shape and flexibility even after the collage was overtaken by the rats’ own cartilage. Although those tests were a success, it’s still too early to test on humans.

Bonassar’s lab has also experimented with synthetic spinal discs, also tested on rats, to help those with chronic back pain. While both the discs and ears are better able to mimic the qualities of human cartilage, the ears are still purely prosthetic: They will look and feel right, but they won’t replace or repair the hearing function of a real ear. At least not yet.

What are the benefits of a 3D printed organ? Would you trust one? Sound off in the comments or tweet the author at @zsniderman.