Composite of porous starch-silk fibroin nanofiber-calcium phosphate for bone regeneration

New bioactive nanobiocomposite scaffolds based on silk fibroin nanofiber-porous starch are presented for potential bone tissue regeneration. The silk fibroin nanofibers were fabricated directly via wet electrospinning using methanol coagulation bath and then the chopped electrospun nanofibers were incorporated into the starch matrix, followed by particulate leaching and freeze-drying. To achieve bioactivity, the calcium phosphate was then deposited throughout the fabricated scaffolds via alternate soaking in saturated calcium and phosphate solutions at 37 °C. The morphology, structure, swelling, and calcium phosphate forming ability of the scaffolds were evaluated and the results indicated that addition of silk fibroin nanofibers into the starch matrix reduced the mean pore size, porosity, and water uptake of the fabricated scaffolds. Moreover, the deposited calcium phosphate layer consists of both brushite and apatitic calcium phosphate. The highest amount of formed calcium phosphate is evident in the starch matrix and increasing the amount of silk fibroin nanofibers decreases calcium phosphate formation. Cell culture experiments with osteoblast-like cells (MG63) on the scaffolds coated with calcium phosphate demonstrated that incorporation of SF nanofibers into the starch hydrogel improves cell viability, proliferation, and attachment.