Mini-review: the role of redox in Dopa-mediated marine adhesion.

3, 4-Dihydroxyphenylanine (Dopa)-containing proteins are key to wet adhesion in mussels and possibly other sessile organisms also. However, Dopa-mediated adhesive bonding is a hard act to follow in that, at least in mussels, bonding depends on Dopa in both reduced and oxidized forms, for adhesion and cohesion, respectively. Given the vulnerability of Dopa to spontaneous oxidation, the most significant challenge to using it in practical adhesion is controlling Dopa redox in a temporally- and spatially defined manner. Mussels appear to achieve such control in their byssal attachment plaques, and factors involved in redox control can be measured with precision using redox probes such as the diphenylpicryl hydrazyl (DPPH) free radical. Understanding the specifics of natural redox control may provide fundamentally important insights for adhesive polymer engineering and antifouling strategies.