Andy Smith. "Gluing with an iron fist: the central role of metals in biological adhesives". Franklin & Marshall College, Lancaster, Pennsylvania. March 2012.
Abstract:
My lab studies the biochemistry and mechanics of adhesive gels. Many gastropod mollusks can form strong attachments using dilute gels. Intertidal limpets, for example, glue themselves onto wet, irregular surfaces so firmly that in some cases they cannot be detached by hand. Some terrestrial slugs can produce a similarly elastic, adhesive defensive secretion. This performance is remarkable given that the glues consist of ~97% water, and appear to be modifications of the animal’s normal lubricating mucus. Our current research focuses on the cross-linking mechanisms that govern gel mechanics. We have found specific proteins that are correlated with increased adhesive strength, and these proteins stiffen gels. We have also found that metal ions play an essential role in the glue, creating stable cross-links despite the presence of water. We are particularly interested in the different ways that metals impact gel mechanics. In the glue of terrestrial slugs, some metals cross-link polymers directly, while other redox-active metals appear to create cross-links through protein oxidation. Protein oxidation is a common post-translational modification that can significantly affect material mechanics.
https://www.ithaca.edu/intercom/article.php/20120404110217192