Preparation of a bio-composite of sericin-g-PMMA via HRP-mediated graft copolymerization

Silk sericin (SS) derived from silkworms has the characteristics of anti-oxidation, antibacterial, and biocompatibility, however, high solubility in water restricted its applications in biomedical fields. In the present work, SS was enzymatically graft-copolymerized with a hydrophobic vinyl monomer of methyl methacrylate (MMA), through a free radical reaction, through the combination use of hydrogen peroxide and horseradish peroxidase (HRP). Efficacy of the HRP-mediated reaction was examined by means of FTIR, SDS-PAGE, and SEC chromatogram. A bio-composite of SS-graft-polymethyl methacrylate (SS-g-PMMA) was constructed subsequently, the corresponding wettability, thermal behavior, and biocompatibility of the obtained composite were examined, respectively. The data reveal that MMA was successfully copolymerized with the reactive sites in sericin chains, resulting in a noticeable increase in the molecular weight. For the membrane of SS-g-PMMA, the surface hydrophobicity was evidently improved compared to that of the untreated, according to the determined data of water contact angle and dissolution ratio. The current work develops an eco-friendly technique for reuse of the industrial waste like sericin, and provides a novel method for preparation of the sericin-based biomaterials as well.