Traditional methods of using pins and screws to mend broken bones is as outdated as those bolts protruding from the neck of Frankenstein's monster. The smarter way to mend bones is to mimic the natural glues used by sea creatures because they are stronger than Superglue, but also work in the wet environment inside the body.
"Smart chemists/innovative thinking" is the key to solving global challenges, according to the world's largest scientific society—the 154,000-members-strong American Chemical Society. In its podcast series called Global Challenges/Chemistry Solutions, the ACS proposes smarter solutions to some of the 21st century's most daunting problems. Its latest podcast hawks an experimental adhesive unveiled earlier this year that can repair bones shattered in battlefield injuries, car crashes and other accidents without the need for the traditional staples, pins and screws. The discovery is featured in ACS' newest podcast (click to listen).
If the chemists have their way, the mechanical fasteners that traditionally hold together bones while they are healing may soon become obsolete. The problem is that some compound fractures and shattered bones are too small to be amenable to mechanical fasteners. To solve the problem, chemists have formulated all sorts of adhesives over the years—but the challenges of surgical glue have so far eluded a foolproof solution.
The biggest problem is that most adhesives are designed to work in air, not the wet environment inside the body where the bones reside. Superglue (cyanoacrylate) is now routinely used in medical clinics to glue outer skin (under trade names like LiquiBand and Dermabond) because it meets two of the three requirements for surgical glues—quick setting and high strength. However, cyanoacrylate fails the third requirement of surgical glues—they must work in the wet environment inside the body.
Sea animals like mussels, however, secrete adhesives that work under water, inspiring chemists to mimic these natural formulations. Back in the 1980s, chemists tried to mimic the glue secreted by mussels, but 30 years of experimentation have yielded no clinical adhesives yet. Now, however, Russell Stewart, Ph.D., claims success may be achieved by mimicking the formula of a nature adhesive secreted by a tiny sea animal called a sandcastle worm.
Sandcastle worms use their glue to construct (no surprise here) sandcastles, which they use to protect themselves from predators (assembling tube structures just large enough for them to live inside). The adhesive that these sea creatures use is now being mimicked in the lab.
The key to the sandcastle worm's glue formulation is its use of coacervates—spherical droplets measured in microns (micrometers)—that encapsulate the glue in a shell of lipids (waxy molecules that repel water). So far, the sandcastle worm's glue has passed the three tests—strength, quickly sets, works underwater—but a fourth goal for commercialization is making it biodegradable, which they plan to tackle next.
