Crosslinking of coiled-coil peptide "bundlemers" into network films

‘Bundlemer’ building blocks are homotetrameric coiled coils assembled from computationally designed peptides in aqueous solution.. These self-assembled bundlemer nanoparticles have great potential for the creation of high performance materials resulting from their coiled coil structure and the ability to almost arbitrarily design their exteriors for desired interbundle interaction. This work focuses on crosslinking bundlemer building blocks using a thiol-ene photo click reaction. Our bundlemers are easily modified to include a thiol reactive group via cysteine incorporation and alkene with the addition of an alloc protected lysine. In the presence of a free radical initiator and UV light, we can crosslink bundlemers into high-modulus gels and crosslinked films. We have explored the effect of peptide sequence, concentration, reactive group ratios, and solvent on the mechanical performance of our resulting materials. Additionally, transmission electron microscopy revealed that the alloc hydrophobically functionalized bundlemers form specific lattice-like nanostructure when cast into films from aqueous solution. The nanostructure formed relative to the bundlemer functionality and solution conditions will be discussed.