Bioengineers print ears that look and act like the real thing

Cornell bioengineers and physicians have created an artificial ear that looks and acts like a natural ear, giving new hope to thousands of children born with a congenital deformity called microtia.

In a study published online Feb. 20 in PLoS ONE, Cornell biomedical engineers and Weill Cornell Medical College physicians described how 3-D printing and injectable gels made of living cells can fashion ears that are practically identical to a human ear. Over a three-month period, these flexible ears grew cartilage to replace the collagen that was used to mold them.

The novel ear may be the solution reconstructive surgeons have long wished for to help children born with ear deformity, said co-lead author Dr. Jason Spector, director of the Laboratory for Bioregenerative Medicine and Surgery and associate professor of plastic surgery at Weill Cornell. "A bioengineered ear replacement like this would also help individuals who have lost part or all of their external ear in an accident or from cancer," Spector said.

Replacement ears are usually constructed with materials that have a Styrofoam-like consistency, or sometimes, surgeons build ears from a patient's harvested rib. This option is challenging and painful for children, and the ears rarely look completely natural or perform well, Spector said. To make the ears, Spector and colleagues started with a digitized 3-D image of a human subject's ear and converted the image into a digitized "solid" ear using a 3-D printer to assemble a mold. They injected the mold with collagen derived from rat tails, and then added 250 million cartilage cells from the ears of cows. The collagen served as a scaffold upon which cartilage could grow.