Building a human body

Scientists at Cornell University and Weill Cornell Medical College in New York have made an ear-ie advancement in the field of prosthesis.

A new study published in the online open-access journal PLoS ONE describes how the researchers successfully produced artificial human ears using 3D printers and cow cells. These are the first artificial ears that look and work like real ones.

"I believe this will be the novel solution reconstructive surgeons have long wished for to help children born with absence or severe deformity of the ear," said Jason Spector, director of the Laboratory for Bioregenerative Medicine and Surgery at Weill Cornell Medical College and one of the study's lead authors, in a statement.

Currently, infants born with ear deformities or people who lose their ears because of cancer or an accident have to settle for unnatural replacements that don't function well. These include ears made from Styrofoam-like materials or ears made by taking pieces of rib bone, carving them into ear shapes and covering them with skin grafts.

The new artificial ears were made by taking digital 3D images of human ears that were fed into 3D printers. The printers spat out hollow ear-shaped molds that were injected with collagen, the main structural protein found in all mammals which serves as a scaffold, and cow cartilage cells. The constructed ears were then implanted on the backs of rats. The whole process took about a week.

Once the ears were created and implanted on rats, they were allowed to grow for three months. Over that time, cartilage grew and replaced the original collagen scaffolds.

If further animal studies on the ear are successful, Spector said his team will move onto human implants. In these cases, ear molds will be implanted under the skin of people in need of artificial ears. According to Spectro, for children born with microtia — a deformity of the outer ear — the best time for an implant will be at the age of five or six years when their ears should be almost fully grown. The cause of microtia is unknown and it's occurrence varies, affecting anywhere from one to four per 10,000 newborns per year.

"Surgery to attach the new ear would be straightforward," Spector said. "The malformed ear would be removed and the bioengineered ear would be inserted under a flap of skin at the site."

Spector said the first human ear implant could be attempted as early as 2016.