Explore the Adhesion Mechanisms of Mussel Adhesive Proteins

The rapid and robust adhesion of marine mussels to diverse solid surfaces in wet environments is mediated by the secreted mussel adhesive proteins which are abundant in a catecholic amino acid, L-3,4-dihydroxyphenylalanine (Dopa). Over the last two decades, enormous efforts have been devoted to the development of synthetic mussel-inspired adhesives with water-resistant adhesion and cohesion properties by modifying polymer systems with Dopa and its analogues. Using the surface forces apparatus (SFA), we systematically explored the adhesion mechanism of various mussel foot proteins. Our SFA results show that mussels achieve strong interfacial binding via balancing a variety of covalent and noncovalent interactions including oxidative cross-linking, electrostatic interaction, metal-catechol coordination, hydrogen bonding, hydrophobic interactions and π–π/cation-π interactions. The SFA can also measure the adhesion and interfacial tension of complex coacervates formed by mussel foot proteins (Mfps). The insights obtained from the understanding of the interaction mechanisms between individual Mfp and disparate substrates provide critical guidance for the design of next-generation wet adhesive materials.