PEGylation of surface protein filaments: Coverage and impact on denaturation

N-Hydroxysuccinimidyl functional polymers for multi-site bioconjugation to amine residues present in α-keratin protein filaments were synthesised via living radical polymerisation. Monomers containing di(ethylene glycol) and poly(ethylene glycol) were employed to give water soluble polymers which were characterised using ¹H NMR and size exclusion chromatography (SEC). The denaturation temperature of the PEG-keratin conjugates was examined using differential scanning calorimetry (DSC) to show that after conjugation to damaged keratinous material, the structural properties of the protein were improved against thermal degradation. Scanning electron microscopy was used to visualise surface coverage.