Polylactic Glycolic Acid-Based Nano Artificial Bone Stent Loaded with Recombinant Human Bone Morphogenetic Protein-2 and Its Performance

Abstract

Pearl layer/polylactic glycolic acid (PLGA) stent and recombinant human bone morphogenetic protein-2 (rhBMP-2) were prepared. Its biocompatibility and osteoblast activity were discussed, and it was applied in the clinical repair of skull defect. Firstly, phase separation/salting out load were adopted to compound different proportions of PLGA and pearl layer powder in different proportions. Besides, PLGA-based nano composite stent was prepared. The physical property synthesized by pearl layer and PLGA in different proportions was detected. The nano stent with the best mechanical performance was selected to load rhBMP-2 and analyze its release characteristics in vitro. The material was soaked in MC3T3-E1 cell solution and then analyze its cell activity. A 5 mm critical bone defect model of rat skull was established and the material was implanted into rat skull defect area. At different time periods, cone beam computed tomography (CBCT) was employed to observe the repair effect of the material on defect areas. The results showed that the prepared PLGA-based nano composite stent showed three-dimensional porous structure, porosity reaching above 80%. When the ratio of pearl layer/PLGA was 7:5, it showed good mechanical strength. The release rate of load rhBMP-2 based on the ratio was accelerated in the first 7 days. In contrast, it gradually became stable after 7 days. The relative proliferation rate of cell solution in the material was over 90% during 7 days. The cytotoxicity is low and the material extract could induce MC3T3-E1 cell differentiation. Under electron microscope, the combination of rhBMP-2/pearl layer/PLGA and autogenous bone showed good effects.