Biocompatibility and safety evaluation of a silk fibroin-doped calcium polyphosphate scaffold copolymer in vitro and in vivo

Abstract

For the reconstruction of cartilage and bone defects, bone repair scaffolds with porous network structures have been extensively studied. In our previous study, CPP-type bioceramics showed higher compressive strength and enhanced degradation after silk fibroin doping, and SF/CPP could be considered a suitable bioceramic for bone tissue-engineering. The aim of this study was to evaluate the biocompatibility and safety of SF/CPP in vitro and in vivo. The cell biocompatibility was evaluated with regard to the cytotoxicity of the scaffolds using co-culture and MTT tests in vitro. The in vivo biocompatibility of SF/CPP was evaluated by implanting the scaffolds in the subcutaneous and intramuscular regions of experimental animals. We established an experimental animal model to prepare critical-sized cranial defects and evaluated the biodegradability and osteoconductivity of the scaffolds in vivo. The results indicated that the SF/CPP scaffold yielded better biocompatibility and safety performance than the CPP scaffold in vitro and in vivo. Immunohistochemistry staining in vivo for OPN and OCN also indicated that SF/CPP has potential to promote the regeneration of critical-sized cranial defects. The SF/CPP scaffold has good biocompatibility and safety for experimental animals and could also serve as a potential effective bioceramic for a range of bone regeneration applications.