Mussels, pounded by the oceans’ waves, fasten themselves to rocks as a matter of survival. Bacteria cast protein nets to hold onto surfaces for dear life. Now MIT researchers have combined the two in a clever new way, producing the best-ever underwater glue inspired by Mother Nature—and a potential replacement for today’s surgical stitches.

The new study, published in Nature Nanotechnology on September 21, describes glue made of super-sticky, self-assembling networks of protein fiber. Led by Chao Zhong—a physical science professor at ShanghaiTech University and former MIT post-doc—the study addresses an enormous need: man’s lack of effective underwater adhesives.

“If you go to the hardware store, pull every glue off the shelf, bring them home and try to stick two things together in a bucket of water, you’re going to find that pretty much nothing sticks,” says Jonathan Wilker, an inorganic chemistry professor at Purdue who was not involved with the study. Water molecules disrupt the attraction between the landlubber glues and the surfaces they’re supposed to bind, making effective underwater glues surprisingly difficult.

One particularly wet environment—the human body—stands to benefit from non-toxic glues that can take the moisture. “Sutures, staples, [and] screws are all really damaging…so we’d probably be a lot better off if we could replace [them] with adhesives,” says Wilker.

To find glues with these elusive properties, many researchers look under the sea. “A lot of underwater organisms need to be able to stick to things, so they make all sorts of different types of adhesives that you might be able to borrow from,” said Tim Lu, a bioengineering professor at MIT and the study’s senior author, in an interview with MIT News. The researchers’ two-year effort to mimic Mother Nature has paid off: their new glue is 50 percent stickier than any other biologically inspired, underwater glue, and the method used to make it is easily adaptable and improvable.

Lu and Zhong used the marine mussel as their muse. The animal can anchor to rocks with an adhesive containing two proteins rich in Dopa, a “superglue” amino acid. Dopa serves double-duty, binding to surfaces while also preventing the glue itself from breaking.

While Dopa is versatile, there’s a catch: any given Dopa molecule can only be either sticky or structural. This keeps “putting Dopa at odds with itself,” writes Herbert Waite, a biochemistry professor at UC Santa Barbara uninvolved with the study. At present, he says, scientists “don’t know enough about how mussels control Dopa,” so previously engineered Dopa-based glues are sticky or structural—not both.

The researchers solved this problem by attaching the genes for the Dopa-rich mussel proteins to bacterial genes responsible for proteins called curli. Normally, curli proteins clump up into complex meshes of fibers called amyloids, allowing bacteria like E. coli to anchor themselves to surfaces and each other.

The group modified E. coli to produce curli with mussel proteins fused on, and once these mashup proteins self-assembled, the resulting amyloids were studded with mussel proteins. Since the amyloids provided the adhesive’s structure, none of the mussel proteins’ Dopa had to be diverted toward holding the glue itself together, allowing all of the Dopa to remain sticky—and allowing massive boosts in the glue’s performance.

Beyond allowing sticky Dopa to thrive, Zhong and Lu’s new adhesive offers additional advantages. The curli proteins’ self-assembling—and consequently self-healing—abilities make the glue highly resilient to changes in temperature and acidity, and Zhong also notes the glue could be used as a self-healing coating.

While the glue’s many strengths are promising—the US Navy funded the research, and Zhong and Lu are in the process of patenting it—there is room for improvement. Zhong emphasizes the need for additional proteins to improve the glue’s stickiness, compatibility with human tissues, and toughness. He also acknowledges that their current, small-scale methods take “a lot of time to get a tiny bit [of adhesive]…We definitely need to scale up for real application.”

Wilker, while acknowledging the production challenges facing Zhong and Lu, remains impressed with their efforts to mimic the mussel. “These biological systems can do things that synthetics—at least up until recently—were not able to do.”