Structure and properties of protein-based fibrous hydrogels derived from silk fibroin and sodium alginate

The biocompatible fibrous hydrogels were formed using physically cross-linked biopolymers. Gelation of silk fibroin (SF, from Bombyx mori silk) aqueous solution was effected by self-assembly and used to entrap blended sodium alginate (SA) without chemical cross-linking. SA was formed into SF/SA fibrous hydrogels with different mixing ratios, forming homogeneous nanofiber networks morphology. Measurements by XRD and FTIR indicated that silk I and silk II structure existed in the fibrous hydrogels and that the secondary structure of fibroin was transformed to β-sheet from random coil during this sol–gel transition process. The compressive stress of SF/SA fibrous hydrogels decreased slightly with increasing of SA content. At the same time, fibrous hydrogels degraded quickly after incubating in protease XIV solution than in PBS solution at 37 °C. For cultivating 12 days, human mesenchymal stem cells proliferated in SF/SA fibrous hydrogels. These fibrous hydrogels may be useful for biomedical applications due to biocompatibility and the widespread utility of hydrogel systems.