Mussels rely on specialized adhesive proteins for attachment to substrates in wet, turbulent environments. Several byssal proteins contain high levels of histidine (His) and 3,4-dihydroxy-L-alanine (DOPA). DOPA is found in high concentration in several adhesive proteins, where it is believed to confer cohesive and adhesive properties to the tissue. Most notably, His occurs in N- and C- terminal regions of byssal collagens where it is mechanically active via formation of strong noncovalent interactions with transition metals (e.g. Fe, Zn and Cu). In this talk I will provide an overview of molecular aspects of mussel adhesion, with an emphasis on bulk and interfacial interactions of DOPA and His.
Single molecule force spectroscopy measurements have shown that DOPA contributes to interfacial adhesion, whereas away from the interface, DOPA participates in covalent and noncovalent cross-linking. Interactions of transition metals with DOPA yield transient coordination bonds that function as dynamic, sacrificial mechanical cross-links that serve to increase the toughness of the tissue. Elsewhere, interactions between His and transition metals are believed to essentially act as sacrificial bonds within the thread, breaking and reforming upon application and removal of a load, respectively. These studies not only provide key insights into the function of wet biological adhesives, but may also inform the design of novel materials with interesting physical properties. I will describe some of these bioinspired polymers and their applications.
See more of this Group/Topical: Materials Engineering and Sciences Division