The ear was developed by Cornell biomedical engineers and Weill Cornell Medical College doctors who believe that their invention will be able to help the thousands of children affected by mictrotia, a congenital deformity where the external ear, known as the pinna, is underdeveloped.
The research, published in PLOS ONE, demonstrated how 3-D printing and injectable gels, made of living cells, are almost indistinguishable from a regular ear.
The flexible ears grew cartilage over three months in order to substitute for the collagen that helped mold them.
"This is such a win-win for both medicine and basic science, demonstrating what we can achieve when we work together," revealed co-lead author Lawrence Bonassar, associate professor of biomedical engineering.
Reconstructive surgeons have waited for the day when they could help kids with ear deformity, and according to co-lead author Dr. Jason Spector, director of the Laboratory for Bioregenerative Medicine and Surgery and associate professor of plastic surgery at Weill Cornell in New York City, this new ear may be what they have been waiting for.
"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."
Materials with a Styrofoam-like uniformity are typically used to make substitute ears. Some doctors, however, construct ears from a person's harvested rib. This can be difficult and painful for kids, while the ears do not usually look entirely normal or function well, according to Spector.
In order to build the ears, Bonassar and team began with a digitized 3-D picture of a normal human ear, and by utilizing a 3-D printer to construct a mold, changed it into a digitized "solid" ear.
When the mold is removed, the high-density gel, created by Cornell, is comparable to the consistency of Jell-o. The collagen acted as a scaffold on which the cartilage was able to grow.
The procedure does not take long at all, according to Bonassar.
"It takes half a day to design the mold, a day or so to print it, 30 minutes to inject the gel, and we can remove the ear 15 minutes later. We trim the ear and then let it culture for several days in nourishing cell culture media before it is implanted."
Microatia affects about 1 to more than 4 per 10,000 babies born every year. Although several kids with microtia are born with an entire inner ear, they suffer from hearing loss because of the absent external structure.
Spector and Bonassar have been working together since 2007, focusing on bioengineered human replacement parts.
Weill Cornell neurological surgeon Dr. Roger Härtl has also collaborated with Bonassar researching on bioengineered disc replacements.
The experts particularly research on replacement human structures that are mainly made of cartilage, such as....:
"Using human cells, specifically those from the same patient, would reduce any possibility of rejection," Spector pointed out.
When children are approximately 5 or 6 years old, their ears have grown 80% of their adult size, therefore, it is the most advantageous time to implant an artificial ear on them.
If future trials show that this procedure is both safe and effective, the first human implant of a Cornell bioengineered ear might occur within just a few years, Spector concluded.
In November 2012, scientists from Wake Forest Institute for Regenerative Medicine presented a new hybrid 3-D printer that simplified the process of making implantable cartilage.