Worm Inspires Medical Adhesive

A bit of chemical magic wrought by a little worm that lives in the sea might one day be used to knit broken human bones back together in the wet environment of the body, said University of Utah bioengineer Russell J. Stewart, who spoke earlier this week at the ACS national meeting in Washington, D.C.

As Stewart described it, the inch-long sandcastle worm lives in a tubular shelter that it builds underwater by gathering broken bits of seashell and sand and secreting a glue to fasten them together. The glue is a colloidal solution of oppositely charged proteins and divalent cations, which is secreted in granules with a pH of about 5. It hardens within 30 seconds when exposed to seawater, which has a pH of about 8.2.

Stewart and his colleagues are designing synthetic mimics of the worm glue made of polyacrylates with phosphate, primary amine, and catechol side chains. Like the natural glue, the synthetic glue can bond materials underwater upon a change in pH. That means it could conceivably be used instead of screws and plates to repair human bones shattered in an accident. As the bones heal, Stewart believes, the glue will biodegrade. His preliminary data indicate the glue isn't toxic to bone.