Photomediated solid-state cross-linking of an elastin-mimetic recombinant protein polymer

Solid-state cross-linking of elastin-mimetic fibers was investigated. Through available lysine residues, an elastin-mimetic protein polymer, poly((Val-Pro-Gly-Val-Gly)(4)(Val-Pro-Gly-Lys-Gly))(39), was modified to incorporate an acrylate moiety. The degree of acrylate functionalization could be varied by changing the reactant ratio of anhydride to elastin. Acrylate modified elastomeric (AME) proteins were associated with lower inverse transition temperatures than the unmodified recombinant protein. The inverse transition temperature in turn dictated the temperature for fiber formation. Fibers and fabric samples of AME were prepared by electrospinning at appropriate temperatures and cross-linked by visible-light-mediated photoirradiation. Fibers in the diameter range of 300 nm-1.5 mum were produced, Fabrics were found to have an average pore size of 78 mum. The occurrence of cross-linking was confirmed by C-13 solid-state NMR with a commensurate increase in modulus.