Mussels inspire adhesive for surgery

Mussels have a knack for clinging to rocks, piers and boat hulls - and in recent years, this has inspired scientists to exploit the shellfish's unique sticky biochemistry to develop medical solutions. The latest: stronger, more effective and safer bioadhesives for post-surgery wound closure.

Researchers at Pennsylvania State University took the biological information and chemical structure of the adhesive protein produced at the foot of the common mussel, and developed a wholly synthetic family of adhesives. Called iCMBAs, the bioadhesives adhere well in wet environments, have controlled degradability, improved biocompatibility and lower manufacturing costs.

Many current adhesives have side effects. Fibrin glues, a human-derived tissue adhesive, for example, are fast acting and biodegradable but have relatively weaker adhesion strength. They may also carry the risk of blood-borne disease transmission and could result in allergic reactions due to animal-based ingredients.

Cyanoacrylate adhesives, or super glues, are very adhesive and set rapidly, but they break down slowly and may cause toxicity. They are often limited to external use.

Neither of these two current products is effective when used on wet tissue, which is needed for internal organ surgery. There are also no commercially available tissue adhesives or sealants appropriate for both external and internal use.

The researchers used the iCMBAs and finger clamping to close three wounds on rats for two minutes. Three other wounds were closed using sutures. The iCMBAs had 2.5 to eight times stronger adhesion in wet tissue conditions compared to fibrin glue. They stopped bleeding instantly and facilitated wound healing. They're also non-toxic and unlikely to cause allergic reactions, although there was some mild inflammation.

"We are still optimising our formulation," says one of the researchers, Yang Jian, an associate professor of bioengineering at Penn State. The goal is to improve the adhesion strength to expand its use for things like broken bones.

In another study last month published in the online journal PNAS Early Edition, mussels inspired University of British Columbia scientists to create a gel that can be painted onto the walls of blood vessels to form a protective barrier. The gel can prevent weakened vessel walls and blood vessel plaque from rupturing, thereby avoiding a potentially life-threatening condition such as heart attack or stroke.

Northwestern University researchers in 2010 also used a mussel-inspired glue to repair ruptures or holes in human fetal membranes, thereby avoiding premature labour or termination of the pregnancy.