Simplified polymer mimics of cross-linking adhesive proteins

Marine mussels and barnacles attach themselves to surfaces by depositing mixtures of proteins and then cross-linking these polymers for curing of their adhesive. Obtaining large quantities of these biological materials for applications development has proven to be problematic. Here we present the synthesis, reactivity, and adhesive characteristics of simplified polymer mimics of bioadhesives. A polystyrene backbone is used to take the place of the protein polyamide chain. Cross-linkable catechol groups are appended to the polystyrene in order to mimic 3,4-dihydroxystyrene (DOPA), the key cross-linking group in mussel adhesive proteins. We show that poly[(3,4-dimethoxystyrene)-co-styrene] polymers exhibit curing analogous to that of the proteins after which they were modeled. The styrene-catechol copolymers also display enhanced adhesion upon cross-linking. This report demonstrates a reductionist approach to developing new polymeric materials on the basis of principles learned from nature.