A sea creature called the sandcastle worm could hold the secret to repairing broken bones in humans. The screws and pins favored by many surgeons today have achieved much success over the years, but they are not suitable for repairing all kinds of fractures. For more precise reconstruction of compound fractures and shattered bones, bioengineers have looked beyond metal hardware and have now duplicated a natural glue secreted by the tiny sandcastle worm. The research team hopes it will provide a better solution to fixing small bones broken in battlefield injuries, car crashes and other accidents.

Project leader Dr Russell Stewart from the University of Utah explains how sandcastle worms use the glue to construct their underwater homes.

“In the wild they glue together sand grains, sea shells and whatever sort of mineral particles they can get a hold of. They use these tentacles to gather those particles, and they bring them in towards their mouth. If they like the size and the texture and the shape, they’ll put a couple of little tiny dabs of glue on it and press it on to the end of the tube … Our interest is in studying that natural adhesive and understanding what it’s made out of, how it works and then copying that with synthetic polymers that we hope to use as medical adhesives.”

A good fit

Adhesives for use in the body must bond to wet objects and not dissolve in water — instead they must displace it. The glue must also solidify in a timely fashion — otherwise it’s useless. Dr Stewart’s new glue must mimic the properties of the sandcastle worm’s.

“It’s a very challenging problem to glue things together in the wet environment, like in open surgery, and the same problems that a surgeon has that would want to glue bones together in open surgery is very similar to the problems that this sandcastle worm faces when it’s gluing sandcastles together underwater.”

In its first stage the adhesive has passed initial toxicity studies in cell cultures, and its strength exceeds that of Super Glue.

“On a 1cm sq. bond we can hang a 40lb bag of potatoes … it might already be adequate for repairing bones that are in non-loadbearing situations, particularly the cranial facial bones.”

Dr Stewart says: “I think the biggest problems are still ahead of us in being able to use this in medicine because of biocompatibility issues, and we want it to degrade, and we need to tune the degradation rates. We’d like for them to be the same roughly as the natural healing process. I think those are going to be bigger problems than we’ve faced so far.”

Watch a narrated video of a sandcastle worm hard at work here.