Traditionally, such patients receive autografts, or skin transplants from donor sites elsewhere on their bodies. But this method has its drawbacks. There is also some scarring at the donor site, where about half the thickness of the dermis has been removed. Surgeons can implant this material, temporarily covered by a thin layer of silicone that protects the area from infectious agents and excessive moisture loss. The collagen-GAG material has pores with carefully controlled diameters that permit cells to grow through the scaffold, which is eventually broken down and dissolved by enzymes.
Cells synthesize a new dermis at the same time that the scaffold is being broken down.
The new skin also grows as the patients do, an important consideration for burned children. The only limitation is that patients with large grafts must avoid strenuous exercise in the sun, because the newly synthesized dermis does not have the original dermis's sweat glands and hair follicles. In addition to several students, Professor Yannas' collaborator has been Dr. John F. Burke, professor emeritus of surgery at Harvard Medical School and Massachusetts General Hospital. Dr. Burke pioneered development of the procedure for preparing wounds for collagen-GAG grafts by removing all traces of dead tissue. He also educated the MIT team as to the specific requirements of wound treatment for massively burned patients, as well as being the first surgeon to use the new treatment with humans.