We exploit information gained from our basic studies of mussel adhesion for the design of synthetic adhesives. Typically, synthetic polymers are chemically derivatized with catechols in the form of DOPA, DOPA peptides, or DOPA-mimetic functional groups (Figure). This approach allows us to employ standard polymer synthetic strategies and to confer the important properties of catechols into these polymers in a straightforward and cost-effective manner. The roles of the catechol in these polymers are the same as in the native mussel proteins, namely interfacial adhesion and cross-linking.
Practical implementation of these polymers as adhesives involves preparation of a precursor solution that is solidified through addition of a reagent that induces either covalent or noncovalent cross-linking (Figure). Our original work involved the use of chemical and enzymatic reagents to induce covalent cross-linking of catechol polymers. More recently, redox reactions between reducible metals (Fe3+ and Ag+) have been employed as cross-linking reagents to form polymer hydrogels.