Regulation of Silk Fibroin Solubility and Performance of Silk Fibroin-Based Hydrogel Adhesives via Partial Hydrolysis

Silk fibroin (SF) derived from Bombyx mori is a promising natural biopolymer for biomedical applications. However, its practical utility is hindered by processing challenges including spontaneous gelation and poor post-lyophilization solubility, primarily attributed to β-sheet formation within its molecular structure. In this study, alkaline hydrolysis was employed to reduce the molecular weight of SF and partially disrupt its hydrophobic domains responsible for β-sheet formation, thereby enhancing the stability of its aqueous solution and the solubility of its lyophilized powder. The hydrolyzed SF was subsequently functionalized with dopamine and integrated into a poly(acrylic acid-co-acrylamide) network to fabricate a bioadhesive hydrogel. Results demonstrated that the alkaline hydrolysis process effectively preserved SF's primary structure while retaining its intrinsic biocompatibility. The dopamine grafting significantly boosted the material's reactivity, resulting in a composite hydrogel with exceptional mechanical strength; its tensile modulus was 3.2 times higher than that of native SF, along with superior tissue adhesion performance, achieving an adhesive strength of 148 kPa on porcine skin. These findings demonstrate a robust strategy for engineering advanced bioadhesive materials from natural silk proteins.