Mimicking Scaffolds for Osteogenesis Based on Poly(vinyl alcohol) Hydrogel with Hard Calcium Phosphate and Soft Silk Fibroin Particle for Bone Regeneration: Molecular Organization, Morphology, Properties, and In Vitro Evaluation

In this study, poly(vinyl alcohol) (PVA)/silk fibroin particle (SFP) hydrogel scaffolds are prepared by mixing compound calcium phosphate (CCP) in different weight ratios (0, 4, 8, and 16%) via the repeated freeze-thawing method. The physicochemical characteristics and biological behavior of the hydrogel are evaluated, and the results show a decreased porous structure of the hydrogel composite with a swelling ability upon CCP addition; however, the mechanical strength and degradation rate increase. Cell attachment and growth analyses demonstrate PVA/SFP/CCP as nontoxic to cells. Furthermore, osteogenesis evaluation shows that the group with 8% CCP in PVA/SFP hydrogel exhibits higher cell adhesion and proliferation than other groups. Additionally, the group exhibits better osteogenic performance than the other groups when alkaline phosphatase activity, total protein content, and calcium deposition are compared. Considered as a mixture, the PVA/SFP/CCP hydrogel is promising for bone tissue engineering applications; particularly, PVA/SFP/8% CCP serves as an optimal choice.