Silk fibroin thermosensitive polymers: Osteogenic, anti-inflammatory, and angiogenic effects for osteomyelitis treatment

Infectious bone defects pose a significant challenge in orthopedics by hindering healing and vascularization. This study explored the impact of fibroin thermosensitive hydrogel on osteogenesis, inflammatory response, and angiogenesis as a potential biomaterial for bone regeneration in osteomyelitis treatment. The biocompatibility of the hydrogel by live/dead staining revealed a high number of viable osteoblast cells after 14 days. ALP activity was significantly increased in all hydrogel formulations, with F3 showing the highest levels of total protein content and calcium deposition, indicating more effective osteogenesis. Gene expression analysis of the osteogenesis-related genes demonstrated that RUNX2 was upregulated by day 7, followed by increased expressions of the OCN and COL-1 genes at later stages. The inflammatory response to F3 was assessed by measuring the nitric oxide (NO) production and pro-inflammatory gene expression in LPS-stimulated RAW 264.7 macrophages. The F3 formulation significantly reduced NO production and iNOS expression, suggesting selective inhibition of the inflammatory pathway. The VEGF-loaded F3 formulation exhibited substantial angiogenic potential, enhancing HUVEC cell proliferation by 140% over 48 h. The osteogenic, anti-inflammatory, and angiogenic effects shown by the F3 formulation were well-suited for applications in osteomyelitis treatment.