Research by Ameya R. Narkar, Jonathan D. Kelley, Rattapol Pinnaratip, and Bruce P Lee has been accepted in Biomacromolecules.
“Effect of Ionic Functional Groups on the Oxidation State and Interfacial Binding Property of Catechol-Based Adhesive” involves the study of marine mussels, which secrete catechol-containing adhesive proteins for underwater binding to surfaces like ship hulls and docks Catechol has been used by scientists and engineers around the world to design synthetic adhesives and coatings for wide ranges of applications. It can be used in tissue adhesive, tissue engineering scaffold, coating for preventing adhesion of bacteria, and so on.
It is shown, however, that in the presence of neutral to basic pH (for example, pH 7.4 in the body or pH 7.5-8.4 in the ocean), catechol oxidizes, leading to reduced adhesive strength. Mussels actually utilize multiple adhesive proteins with various ingenious designs to prevent catechol oxidation and to preserve strong adhesion. The adhesive proteins exhibit antioxidant properties, hydrophobicity for avoiding contact with basic sea water, and other methods in order to optimize adhesion.
We found that incorporation of acidic functional groups in the adhesive network can also prevent catechol oxidation, preserving strong adhesion, even up to a pH of 8.5. This is a much simpler approach than what the mussels employ and potentially easier for designing synthetic mimics of these adhesive proteins. This means that we will be able to design biomimetic adhesives for biomedical applications and underwater applications, which are the basic pH environments of interest.