Fabrication of Silk Scaffold Containing Simvastatin-Loaded Silk Fibroin Nanoparticles for Regenerating Bone Defects

Background: In the present study, a tissue engineered silk fibroin (SF) scaffold containing simvastatin-loaded silk fibroin nanoparticles (SFNPs) were used to stimulate the regeneration of the defected bone. Methods: At first, the porous SF scaffold was prepared using freeze-drying. Then simvastatin-loaded SFNPs were made by dissolvation method and embedded in the SF scaffold. Afterwards, the scaffold and the NPs were characterized in terms of physicochemical properties and the ability to release the simvastatin small molecule. Results: The results exhibited that the SF scaffold had a porous structure suitable for releasing the small molecule and inducing the proliferation and attachment of osteoblast cells. SFNPs containing simvastatin had spherical morphology and were 174 ± 4 nm in size with -24.5 zeta potential. Simvastatin was also successfully encapsulated within the SFNPs with 68% encapsulation efficiency. Moreover, the small molecule revealed a sustained release profile from the NPs during 35 days. The results obtained from the in vitro cell-based studies indicated that simvastatin-loaded SFNPs embedded in the scaffold had acceptable capacity to promote the proliferation and alkaline phosphatase production of osteoblast cells while inducing osteogenic matrix precipitation. Conclusion: The SF scaffold containing simvastatin-loaded SFNPs could have a good potential to be used as a bone tissue-engineered construct.