A close bond: A scanning electron microscope image of two glass beads cemented together by a sandcastle worm and removed from the worm’s tube (inset). The larger image is a close-up of the connection, which was made using the worm’s adhesive.
Stewart and his colleagues believe the adhesive can be used as a complement to wires, pins, and plates–large pieces could be held in place with hardware, while small pieces could be glued back in. And in cranial-facial fractures, where using pins and screws can cause permanent cosmetic damage, the glue could potentially be injected with a syringe, avoiding open surgery.
“One of our challenges is to hold very small pieces in very precise alignment. We just need to hold them there until they heal, just six weeks,” says Thomas Higgins, an orthopedic surgeon at the University of Utah’s School of Medicine who specializes in joint fractures and has consulted with Stewart on the adhesive’s clinical applications. “To have something that is liquid and would assume a more rigid state when you put it [in the body], that would be much more easily applicable and much more versatile than what we use now,” he says. “This is still preliminary, but it shows a lot of promise.”
Beyond bonding bones, the adhesive holds promise for a number of wet-environment applications–everything from mending cracked teeth to repairing corrosive cracks on ships out of dry dock. “It will be really interesting for a dentist or orthopedic surgeon to consider [this type of material] as a strategy for bone and tooth repair,” says Herbert Waite, a biochemist at the University of California, Santa Barbara who was not involved in the research.
Karp notes that there’s still a lot of work to be done. “Just the idea of forming glue in the presence of blood may be very different than forming it under seawater or under lab conditions,” he says. But he believes that the group is off to a good start. “I think it’s a really interesting and novel approach, to better understand the biology of the sandcastle worm to create new adhesives,” Karp says. “Evolution is the best problem solver. There’s nothing that can compete with it.”