Genipin-Cross-Linked Layer-by-Layer Chitosan/Hydroxyapatite Composite Rod for Bone Fracture Fixation

Abstract

The synthesis and optimization of chitosan-based inorganic/organic composites have gained growing interest in the last years. In the current study, genipin crosslinked hydroxyapatite/Chitosan (HA/CHI) composite rods (GCHR), which had been prepared and reported in our prevenient studies, were further evaluated via their formation of layer-by-layer structure, cross-linking degree and so on. The cross-linking degree in the range of 28.73∼43.32% was moderate for the in situ periodic precipitation and the formation of homogeneous HA/CHI/Genipin composite rods. In this range the composite rods could obtain a complex structure combined with layer-by-layer structure and radial spokes structure. Benifiting from the special structure, the rods can obtain superior mechanical properties and become fresh device for internal fixation of fracture. Mouse bone marrow mesenchymal stem cells (mBMSCs) were co-cultured with extract of the GCHR100 rods to evaluate the cytocompatibility of the composite. The results showed that the leachate of the GCHR100 rods significantly up-regulated osteogenesis-related genes like ALP, Runx2 and OCN after 7 days compared with control (P< 0.05).