Exploiting mussels’ iron grip

Mussels’ ability to cling to rocks in the ocean while being continuously battered by waves has prompted numerous scientists to design strong water-based adhesives for use in surgery and other applications. Now, taking inspiration from mussels’ byssal threads—the ultrathin, ropelike structures the mollusks use to lash themselves to rocks—Megan T. Valentine of the University of California, Santa Barbara, and coworkers have created a dry polymer that is strong, as well as tough and flexible (Science 2017, DOI: 10.1126/science.aao0350). The tricks scientists use to improve a material’s properties often come at a price. For example, strengthening a polymer by introducing more cross-links can make it brittle. To avoid some of these trade-offs, Valentine looked to the chemistry of mussels’ byssal threads. These stiff yet stretchy cylinders of collagen are surrounded by protein-rich cuticles and can bounce back into shape reasonably well. One key piece of chemistry that mussels use in those