Enhancing in vitro bioactivity and in vivo osteogenesis of organic-inorganic nanofibrous biocomposites with novel bioceramics

Fabricating bioactive nanofibrous scaffolds from biodegradable polymers to mimic native tissue is an important approach in repairing bony defects. Silk fibroin (SF) may contribute to bone regeneration because of its excellent mechanical properties, slow degradability, and low osteoconductivity. A combination of bioceramic-polymer materials is generally used to provide an improved osteoconductive environment for bone healing. This study attempts developing for the first time an electrospun SF-based biocomposite system by introducing new bioceramics based on mesoporous bioactive glass/hydroxyapatite nanocomposite (MGHA). The addition of MGHA into the SF matrix could regulate the physicochemical properties and surface hydrophilicity, but induce weakened tensile properties as compared to pure SF. The excellent apatite-formation ability of a MGHA-introduced nanocomposite also improved the bioactivity of the composite. The biphasic composite increasingly degraded in PBS or enzyme solution in vitro compared with pure SF. In vivo evaluation of bone formation confirmed that SF/MGHA is more advantageous in bone reconstruction than the SF group for cranial bone defects. These results indicate the suitability of the SF/MGHA composite system in bone defects, demonstrating its potential application in bone tissue regeneration.