Biodegradable supports are the most desirable because the new tissue will develop its own supportive matrix in time. Mikos' lab has designed materials that will dissolve at the same rate as the bone growth, so that by the time cells have matured the polymer has disappeared. Getting bones to grow Facial bones, such as a jaw removed for cancer, are of particular interest to Mikos and surgeon Michael Miller of the M.D. Anderson Cancer Center in Houston. The current practice is to take bone from the hip or ribs and manufacture it into a new jaw. Engineering bone offers a much better alternative.
Bone growth poses a challenge because it requires a blood supply.
Mikos' group has learned to to grow bone in vivo on a sheep by using its rib as a platform and an artery to feed the implanted cells. For tendons and cartilage, Caplan and his team place mesenchymal cells into a collagen gelatin-like material. For cartilage, the cells are placed in a cube and then inserted into the damaged area. Animal studies show that holes cut into a knee cap and filled with the gel heal normally and completely. That is significant, considering cartilage does not grow back on it own.