Those who have tried to pry a mussel from anything from wood to rock know how stubborn the underwater mollusks are—and their gluey secret has long captivated scientists. For years, researchers have attempted to replicate the extraordinary adhesive and its properties in the lab, targeting some of the eight proteins that mussels secrete and use to coat an organ called a foot that mussels use to attach to surfaces.
Credit: CC0 Public Domain Now, using a novel method to arrange molecules, researchers at Northwestern University have created a material that performs even better than the glue they were trying to mimic. Their findings, to be published March 3 in the Journal of the American Chemical Society, expand on how these protein-like polymers can be used as a platform to create new materials and therapeutics. "The polymer could be used as an adhesive in a biomedical context, which means now you could stick it to a specific tissue in the body," said Northwestern's Nathan Gianneschi. "And keep other molecules nearby in one place, which would be useful in wound healing or repair." Gianneschi led the study and is the Jacob and Rosaline Cohn Professor of Chemistry in the Weinberg College of Arts and Sciences at Northwestern. Proteins like those secreted by mussel feet exist around nature. Evolution has made a habit of creating these long, linear chains of amino acids that repeat over and over (called tandem repeat proteins, or TRPs). Appearing at times stretchy, strong and sticky, the protein frameworks show up in insect wings and legs, spider silk and mussel feet. Scientists know the exact primary sequences of amino acids that make up many such proteins, yet have trouble replicating the complicated natural process while still maintaining the extraordinary qualities. The paper's first author Or Berger, a postdoctoral researcher in Gianneschi's lab who studies peptides—these very chains of amino acids—came with an idea for how to arrange amino acid building blocks differently to replicate the properties rather than directly copy the structure of mussel proteins. By taking the building block of one of the proteins (the repeat decapeptide, a 10-amino acid sequence that makes up the mussel foot protein),…