Andy Smith was awarded a three year grant from the National Institutes of Health (NIH) for $200,520. This grant will support research with undergraduate students on biological adhesives. The title of the project is, "The mechanism of crosslinking by proteins that create adhesive gels."
A wide variety of animals use gel-based glues to create strong attachments. These gels consist of roughly 97% water, yet they can create attachments that approach the strength of the solid cements of other marine animals. The ability to form such strong attachments in wet environments with a deformable, water-based adhesive would be highly useful for a medical adhesive. Thus, it is important to determine how these adhesives function. A key component of the gel-based glues of molluscs is the presence of glue proteins, which non-specifically stiffen gels. The goal of the proposed research is to determine the mechanism by which the glue proteins do this. It is hypothesized that the glue proteins crosslink larger polymers through a combination of ionic and hydrophobic interactions. Three approaches will be used to test this. First, the glue proteins from terrestrial snails or slugs will be purified, then added to commercial gel-forming polymers. The gel-stiffening ability of the glue proteins will be measured under a variety of conditions that interfere with specific interactions. Second, column chromatography will be used to measure the ability of the glue proteins to interact with different substrates under the same kind of conditions. Finally, mass spectrometry and Polymerase Chain Reaction (PCR) based methods will be used to determine the primary sequence of one of the main glue proteins. This will help identify possible cross-linking regions and give further insight into how they may function. The long-term goal of this research is to provide sufficient information to design a practical adhesive using a biomimetic approach. This is relevant to public health because there is a clear need for improved medical adhesives. Once the remarkable natural adhesives used by animals are understood, it may be possible to design adhesives with similar properties that could be used in a wide variety of medical applications.