Doctors and bioengineers at Cornell University have created artificial ears using three-dimensional printing and injectable molds. The ears look and act just like a natural ear and could, within three years, offer a new option for thousands of children born with external ear deformations.

Replacement ears are often constructed with materials that have a Styrofoam-like consistency or built by surgeons from a patient’s harvested rib. But such ears rarely look natural or perform well, says Jason Spector, co-lead author of an article about the project in the journal PLOS One.

If all future safety and efficacy tests work out, it might be possible to try the first human implant of a Cornell bioengineered ear in as little as three years, Spector says.

The article details how Cornell biomedical engineers and Weill Cornell Medical College physicians created the flexible ears over a three-month period, growing cartilage to replace the collagen that was used to mold them.

Lawrence Bonassar, co-author of the paper and an associate professor of biomedical engineering at Cornell and colleagues started with a digitized three-dimensional image of a human subject’s ear, and then converted the image into a digitized “solid” ear using a 3D printer to assemble a mold, according to the university.

The process is fast, says Bonassar. It takes half a day to design the mold, a day or so to print it, 30 minutes to inject the gel, and then the ear can be removed 15 minutes later. The researchers then trim the ear and let it culture for several days in nourishing cell culture media before it is implanted.

The incidence of microtia, which is when the external ear is not fully developed, varies from almost 1 to more than 4 per 10,000 births each year. Many children born with microtia have an intact inner ear, but experience hearing loss due to the missing external structure.