Mussel-inspirit polymerization: „The enzyme free route of an tyrosinase activated polymerization“

• Applicant: Professor Dr. Hans Gerhard Börner
• Subject Area: Polymer Materials
• Term: from 2013 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 234499734

Research objective of the proposal is the introduction of a novel class of macromonomers, which provides the possibility to exhibit a polymerization after being enzymatically activated. As a result of the enzyme activated polymerization, segmented copolymers with multifunctional character will be obtained. The polymerization process is derived from the fundamental cross-linking principle occurring in mussel adhesion processes. Similar chemistry that leads during byssus formation of marine mussels to cross-links between mussel foot proteins should be employed to generate linear polymers with repetitive monomer sequences.During mussel adhesion, enzymatically controlled processes occur, which synchronize the activation and crosslinking of a set of mussel foot proteins. The process is highly complex and far from being fully understood, but the fundamental cross-linking principle can be abstracted and applied towards linear polymerization of designed oligopeptides (macromonomers) yielding segmented copolymers.The enzymatically activatable and polymerizable oligopeptides require to have one tyrosine residue and one lysine or cysteine residue. This will allow for the two-step polymerization process to occur: First the non-polymerizalble oligopeptide will be enzymatically activated by tyrosinase, generating a 3,4-dihydroxyphenylalanin derivative (L-Dopa derivative) from the tyrosine residue. Subsequently, polymerization can occur by polyaddition mechanism involving the michel addition of the nucleophilic side chain functionality of lysine or cysteine (amino or thiol) to the L-Dopa derivative leading to lysinyl-DOPA- or cycteinyl-DOPA coupling products, respectively.Within the project the minimum requirements for a tyrosinase activatable macromonomer and the maximum tolerance of the process towards deviation from biologically derived tyrosinase substrates will be investigated. A set of functional macromonomers will be synthesized, the tyrosinase activation-kinetics and the following polymerization mechanism will be investigated. The polymerization process will be adapted to a larger scale of up to 1-10 g macromonomers and the multifunctional polymers will be deeply characterized, before being tested as coatings for various material surfaces. Besides revealing insight into fundamental aspects of bioadhesion, interesting polymers will be accessed that might have potential as adhesives, (nano)particle stabilizers, or crystal growth modifiers.

• DFG Programme: Research Grants