Preparation and Performance Study of Regenerated Tussah Silk Protein/Sodium Alginate/Polyvinal Alcohol Composite Film Materials

The inherent brittleness of regenerated tussah silk proteins and the difficulty in preparing a uniform sol pose significant challenges to subsequent material fabrication, resulting in poor mechanical properties. To address this issue, we employed a formic acid-CaCl₂ system to dissolve degummed tussah silk for the preparation of regenerated tussah silk protein, followed by characterization of its chemical structure and thermal stability by FTIR, XRD, SDS-PAGE, DSC and TG analyses. Subsequently, the regenerated tussah silk proteins were blended with sodium alginate (SA) and polyvinyl alcohol (PVA) to cast films, which were then crosslinked with CaCl₂ to fabricate composite film materials. The microscopic morphology, mechanical strength, water resistance, hydrophilicity, cytotoxicity (via MTT assay) of the prepared film materials were systematically characterized. Results showed that the molecular weight of the regenerated tussah silk proteins prepared using the formic acid-CaCl₂ system ranged from approximately 70 to 180 kDa, with a secondary structure predominantly composed of β-sheet. The genipin-treated regenerated silk protein formed a uniform and stable sol, and its film-forming property was significantly enhanced when blended with SA and PVA. After further cross-linking with CaCl₂, a series of biodegradable film materials exhibiting ideal toughness, strength, water resistance, hydrophilicity and non-cytotoxicity were successfully fabricated, demonstrating promising potential for applications in skin wound healing, drug sustained-release, and related biomedical fields.