A 20-year-old woman born with a small and malformed ear received a new 3D-printed ear made up of her cells. The ear, which was designed to perfectly match her other ear, was successfully transplanted onto her head earlier this year in a clinical trial.

The company behind this impressive feat of tissue engineering is 3DBio Therapeutics.

“It’s definitely a big deal,” Carnegie Mellon biomedical engineering researcher Adam Feinburg told The New York Times. “It shows this technology is not an ‘if’ anymore, but a ‘when,’” Feinburg, who was not part of the project, adds.

Remarkably, the company says that the ear will continue to grow, generating new cartilage tissue.

How did they do it?

To build the ear, the company used about half a gram of the patient’s cells and grew them into billions of new cells using a “proprietary technology.” The next step was for a special 3D printer to print the ear with collagen-based “bio-ink.”

“It comes in as a biopsy from the patient, and it leaves a living ear,” explains 3DBio CEO Daniel Cohen.

While the company has undergone the necessary federal regulator reviews, however, they remain secretive about the technical details of the procedure. This could also be because the clinical trial, which involves 11 patients, is still in progress.

“As a physician who has treated thousands of children with microtia from across the country and around the world, I am inspired by what this technology may mean for microtia patients and their families,” says Arturo Bonilla, the surgeon who transplanted the ear.

“This study will allow us to investigate the safety and aesthetic properties of this new procedure for ear reconstruction using the patient’s own cartilage cells.”

Now, 3DBio Therapeutics hopes to apply its technology to other body parts such as spinal discs, noses, and rotator cuffs.