Synthetic Polypeptide Mimics of Marine Adhesives

TLDR

The study aimed to investigate how varying functional group composition in DOPA‑containing copolypeptides influences adhesive and cross‑linking behavior. Copolypeptides were synthesized by ring‑opening polymerization of NCA monomers and, upon oxidation with agents such as O₂ or H₂O₂, formed cross‑linked networks that adhered moisture‑resistantly to metals, glass, and plastics. Optimized systems produced adhesive bonds comparable in strength to natural marine proteins, with performance dependent on oxidation conditions and scalable without enzymes.

Abstract

Water soluble copolypeptides containing l-dihydroxyphenylalanine (DOPA) and l-lysine were prepared by ring-opening polymerization of alpha-amino acid N-carboxyanhydride (NCA) monomers. We have prepared a range of different copolymers to probe the effects of functional group composition on adhesive and cross-linking behavior. Aqueous solutions of these copolymers, when mixed with a suitable oxidizing agent (e.g., O2, mushroom tyrosinase, Fe3+, H2O2, or IO4-), formed cross-linked networks that were found to form moisture-resistant adhesive bonds to a variety of substrates (e.g., aluminum, steel, glass, and plastics). It was found that successful adhesive formation was dependent on oxidation conditions, with chemical oxidants giving the best results. Optimized systems were found to form adhesive bonds that rival in strength those formed by natural marine adhesive proteins. Our synthetic systems are readily prepared in large quantities and require no enzymes or other biological components.