Bivalve mollusks, such as the blue mussel Mytilus edulis, inhabit coastal waters, attached firmly to rocks and other fixed substrates despite the wet environment and continual, sometimes intense, tidal and wave action. Mussels achieve this remarkable feat by secreting unique protein-based adhesive materials that cement them to their chosen surfaces. These adhesives cure quickly and hold fast, even in wet conditions and on all kinds of surfaces—properties that make them well-suited to myriad clinical applications in addition to their original purpose.

Hemostasis, wound closure and healing, dental and bone repair, tissue engineering, device implantation and drug delivery could all benefit richly from these characteristics. As a result, various researchers have attempted to develop bioadhesives based on mussel adhesive proteins, either by isolating and purifying the natural compounds or by synthesizing their mimics in the lab. Jian Yang (The Pennsylvania State University, University Park, and University of Texas at Arlington) and colleagues took the latter approach and now report the creation of injectable citrate-based mussel-inspired bioadhesives (iCMBAs) and the successful use of these synthetic polymers in wound-healing studies in rats.

Wet adhesion strength was 2.5–8 times stronger for iCMBAs than for fibrin glue, a tissue adhesive often used in clinical hemostasis. The iCMBAs also had controlled biodegradability, mechanical properties similar to those of tissue and very high cell and tissue compatibility in vitro and in vivo. They stopped bleeding instantly without the need for sutures and successfully closed relatively large incision wounds (2 cm long × 0.5 cm deep) on the dorsum of Sprague-Dawley rats within 2 minutes, a result that cannot be accomplished with fibrin glue. Furthermore, iCMBAs accelerated wound healing and were completely degraded and absorbed within 28 days without provoking an excessive inflammatory response (Biomaterials 33 7972–7983; 2012).

Credit: iStockphoto.com/GeorgeBurba

The results suggest that iCMBAs are suitable candidates for biological and surgical applications including wound closure; tissue grafts (e.g., for hernias, ulcers or burns); hemostasis; sealing of vascular anastomoses; and treatment of gastrointestinal fistulas, leaks, bleeding or perforation. “There are so many applications that you can use this glue for to help in surgery,” Yang noted in a press release.

Yang and his colleagues plan to improve the iCMBA formula. “We are still optimizing our formulation. We are still trying to make the adhesion strength even stronger. We can introduce another component with antimicrobial properties, so it can do two functions at once,” stated Yang.