Sitting on a shelf in Dr. Molly Stoichet’s office in a glass test tube is a tiny piece of…bone? Well, not quite. It looks like bone, acts like bone, promotes bone growth, but is not actually bone.
The efforts of Dr. Stoichet and Dr. Jeffrey Davies, of the U of T’s Institute for Biomaterials and Biomedical Engineering (IBBME) and their own firm BoneTec, have resulted in the development of a polymer called Osteofoam. It is designed to imitate trabecular bone, the form of bone that promotes and allows for faster bone healing, by acting as a scaffold on which new bone can form.
The biodegradable polymer, similar to the substance used in dissolving sutures and stitches, is inserted into a break in the bone. Since this sort of material has already been used for years in the human body, its safety is virtually guaranteed. Prior to insertion the scaffold is seeded with bone marrow cells, which then differentiate inside the body into osteoblasts and osteoclasts, the cells responsible for the growth and breakdown of bone. As new bone grows throughout the scaffold, the polymer slowly dissolves, leaving only healthy bone in its place. Hence Osteofoam accelerates re-growth of bone and helps return strength to the limb.
Other substances for supporting bone growth have been developed, but none have been as successful as this one. Dr. Stoichet credits the spongy consistency of the material-it is 92 per cent air.
In other materials cells often became blocked up and could not penetrate deep enough to form strong bone. The interconnected pores in Osteofoam make it easy for both cells and nutrients to move through the material.
Dr. Stoichet and Dr. Davies’s work could revolutionize the way severe bone loss is treated, in situations where there is not enough bone present for the body to heal itself naturally as with a cast.
