The successful treatment of bone infections is a major challenge in the field of orthopedics. There are some common methods for treating bone infections, including systemic antibiotic administration, local nondegradable drug vehicles, and surgical debridement, and each of these approaches has advantages and disadvantages. In the present study, the antibiotic vancomycin (VANCO) was loaded in silk fibroin nanoparticles (SFNPs) and the complexes were then entrapped in silk scaffolds to form sustained drug delivery systems. The release kinetics of VANCO from SFNPs alone and when the SFNPs were entrapped in silk scaffolds were assessed at two different pH values, 4.5 and 7.4, that affected the release profiles of VANCO. Disk diffusion tests performed with pathogens causing osteomyelitis methicillin-resistant Staphylococcus aureus (MRSA) showed antibacterial activity of the released drug at two different pH values. Additionally, injection of 8 × 10 CFU MRSA in rat's tibia induced severe osteomyelitis disease. Radiographic and histopathological analyses were performed to evaluate the effectiveness of treatment after 6 weeks. The VANCO-loaded silk fibroin nanoparticles entrapped in scaffolds reduced bone infections at the defected site with better outcomes than the other treatment groups. In conclusion, the delivery system with good biocompatibility and sustained release properties would be appropriate for further study in the context of osteomyelitis disease.

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One of the main challenges of using biomaterials for inducing bone regeneration is the bacterial resistance before complete bone repair. Biomaterials with both antibacterial and bone regeneration properties are more promising for bone repair. In the present study, vascular endothelial growth factor (VEGF) was loaded on silk fibroin nanoparticles (SFNPs) and then embedded in silk scaffold containing vancomycin to form a dual drug release system. The chemical and physical properties of the fabricated structure were confirmed by Fourier transform infrared, scanning electron microscopy, and ζ-potential analysis. The size of spherical SFNPs was ∼92 nm. The release kinetics of vancomycin and VEGF showed that ∼99.56% of vancomycin and ∼14% of VEGF were released during 21 and 28 days, respectively. The bioactivity of VEGF was ∼75%. Disk diffusion test confirmed the ability of this drug delivery system against methicillin-resistant Staphylococcus aureus (MRSA). Moreover, expression of the endothelial markers (FLK-1, vWF, and VE-cadherin), alkaline phosphatase, and matrix mineral production were higher in VEGF loaded groups. Taken together, the results indicated that the fabricated codelivery system was able to simultaneously deliver antibiotic and angiogenic factor, which can be considered as a potential candidate for the treatment of contaminated bone injuries.