Boffins at Cornell University have been showing the potential for 3D printers by creating a replacement ear using a 3D printer and an injection of living cells.

Once refined, the technique will allow biomedical engineers to print customised ears for children born with malformed ones, or people who have lost theirs and have not found them down the back of the sofa. While prosthetic reconstructions are suboptimal; they don't look realistic and they lack the qualities of real tissue, the 3D printer versions are pretty good.

Alyssa Reiffel, Lawrence Bonassar, Jason Spector, and colleagues employed a 3D printing technique they refer to as high-fidelity tissue engineering. They used cartilage from a cow, but think that one day should be able to cultivate enough of a person's ear so that the growth and implantation can happen right there in the lab.

It all starts with a 3-D camera that rapidly rotates around a head for a picture of the existing ear to match. It beams the ear's geometry into a computer. From that image, the 3-D printer produced a soft mold of the ear. Bonassar injected it with a special collagen gel that's full of cow cells that produce cartilage - forming a scaffolding. Cartilage grows to replace the collagen and after three months, it appeared to be a flexible and workable outer ear.