To grow the new ear, researchers created a titanium wire frame modeled after the human ear. They filled in the wire frame with collagen taken from cows. In the future, human replacement ears may use collagen taken from the patient, Thomas Cervantes, one of the researchers and a surgeon at Massachusetts General Hospital, told the BBC. The researchers then seeded their scaffold with cartilage cells taken from sheep. …The team created an adult-size ear and implanted it onto a rat. The point of the implantation is to check that the ear doesn’t lose its shape after implantation and healing.