Superglue from the sea

The secret of how mussels glue themselves to rocks, ropes and boats has been unpicked by chemists. The discovery could lead to new surgical adhesives or paints that stop barnacles from sticking to the underside of boats.

Mussels produce a powerful glue to maintain their grip on whatever surface they call home. Researchers have attempted to harness this glue, either by harvesting it from the mussels themselves or by trying to manufacture the protein in bacteria or tobacco plants.

Those efforts could be helped by Jonathan Wilker and his colleagues at Purdue University in West Lafayette, Indiana. They have determined that the key ingredient to the glue's stickiness is charged atoms of iron (Fe3+) collected by the mussels from sea water1.

Wilker's team studied the glue secreted by blue mussels (Mytilus edulis). "It's based on crosslinked protein molecules," he explains. "But iron is the curing agent that sets it solid."

The glue - or a synthetic version of it - would be a valuable asset to surgeons. It is compatible with biological tissue, and forms a strong bond in wet conditions.

Knowledge of the glue's chemistry could also benefit the shipping industry. Without protection, ships quickly become covered with barnacles, algae and other organisms, which slow them down.

Many current protective paints work by releasing toxic copper ions into the water, eradicating the animals before they can attach themselves. More environmentally friendly coatings might release specific chemicals to interrupt the setting process, Wilker suggests.

References

1. Sever, M. J., Weisser, J. T., Monahan, J., Srinivasan, S. & Wilker, J. J. Metal-mediated cross-linking in the generation of a marine-mussel adhesive. Angewandte Chemie International Edition, doi:10.1002/anie.200352759, (2004).