Washington: Bio-engineers and physicians have synthesised an artificial ear with the help of 3-D printing and injectable moulds, offering new hope to thousands of children born with microtia.

Many children born with microtia, a congenital deformity that leaves the external ear under developed, do have an intact inner ear, but experience hearing loss due to the missing external structure.

Weill Cornell Medical College biomedical engineers and physicians described how 3-D printing and injectable gels made of living cells, grew cartilage to replace the collagen that was used to mould them, over a three month period, the journal Public Library of Science One reports.

"This is such a win-win for both medicine and basic science, demonstrating what we can achieve when we work together," said Lawrence Bonassar, associate professor of biomedical engineering, who co-led the study, according to a Weill Cornell statement.

The novel ear may be the solution reconstructive surgeons have long wished for to help children born with ear deformity, said study co-author Jason Spector, associate professor of plastic surgery at Weill Cornell in New York City.

"A bio-engineered 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, Bonassar 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 mould.