Synthesis of Small Molecule Foot Protein Mimics
Research into bioinspired wet adhesion has brought forth may advances in medicine, materials science, and surface chemistry, and promises many more in the future, from surgical adhesives to self-healing materials. The most studied example of wet bioadhesion is that of the marine mussel. Many studies have shown that L-3,4 dihydroxyphenylalanine (Dopa) plays a major role in mussel adhesion and is a major component (up to 35 mole percent) in mussel foot proteins (Mfps). It also has be noted that mussel foot proteins contain an abnormally high percentage of positively charged amino acids, often adjacent to Dopa. It was previously demonstrated that lysine plays a major role in mussel adhesion by out-competing potassium cations for surface sites, allowing catechol to bind the underlying oxides. In this project we examine the function of other positively charged amino acids found in Mfps by synthesizing small molecules comprised of 2-3 catechols bound to the selected amino acids on a tris(2-aminoethyl)amine backbone. Compounds will be analyzed using electron spray mass spectrometry and H1 nuclear magnetic resonance, adhesive properties will be determined using a surface force apparatus. Arginine and histidine are expected to play a similar role to that of lysine.. In addition, the pKa of the histidine sidechain is within the pH range of our adhesion experiments, allowing us to investigate both the charged and uncharged version of the sidechain. Overall this will give us a better understanding of mussel foot protein function and structure and enable further advances in bioinspired materials.