They injected animal-derived collagen into that ear mold, and then added nearly 250 million cartilage cells. The collagen served as a scaffold upon which cartilage could grow. Collagen is the main structural protein in the body of every mammal. Animal-based collagen is frequently used for cosmetic and plastic surgery. This high-density collagen gel, which Cornell researchers developed, resembles the consistency of flexible Jell-O when the mold is removed.
"The process is fast," Dr. Bonassar says. "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 a nourishing cell culture medium before it is implanted."
During the three-month observation period, the cartilage in the ears grew to replace the collagen scaffold. "Eventually the bioengineered ear contains only auricular cartilage, just like a real ear," says Dr. Spector.
Previous bioengineered ears have not been able to maintain their shape or dimensions over time, and the cells within them did not survive.
The researchers are now looking at ways to expand populations of human ear cartilage cells in the laboratory so that these cells can be used in the mold.
Dr. Spector says the best time to implant a bioengineered ear on a child would be when they are about 5- or 6-years-old, because at that age, ears are
80 percent of their adult size. "We don't
|Contact: Lauren Woods|
Weill Cornell Medical College