The Preparation And Cytology Study Of The Organic-inorganic Hybrid Material With Micro-nano Structure For Bone Repair

Natural polymer materials such as chitosan(CS),hyaluronic acid(HYA),and collagen(Col),due to have good biocompatibility and have been widely used for bone repair material preparation now.The synthetic polymer materials such as poly(lactic acid)(PLA)usually have good mechanical properties.Compounding natural polymer materials and synthetic polymer materials would be a potentially choose to prepare the novel material for bone repair.In this study,chitosan(CS),collagen(Col),and poly(lactic acid)(PLA)were employed as organic matrix,Calcium and phosphate salt solution were the precursors of the inorganic phase.According to the biomimetic synthesis and freeze-drying techniques,we finally build a typical three-dimensional of micro-nano structure scaffold and obtained the ideal scaffold for bone repair.This experiment finally established three composite scaffolds as CS/nHAP,CS/Col/nHAP and CS/Col/PLA/nHAP.Functional group such as carboxyl,hydroxyl,amino and amide group and so on provide the position for hydroxyapatite uniform crystallization.The microstructure and physicochemical properties were system analyzed using SEM-EDX,FT-IR,XRD,et al.The contact angle,porosity,mechanical properties and cytocompatibility of these composite scaffolds were also determined.The second enzyme digestion-organization cultivation method is used to extrac osteoblast cells from newborn SD rats.This paper adopts the giemsa's staining,MTT,Hoechst 33258 and AO/EB methods to evaluate characteristics and biocompatibility of the scaffold.SEM showed that these composite scaffolds all possessed interconnected porous structure,with the pore size at 50-200 ?m,porosity results also proved to this.The nano-particles were formed in situ with relatively homogeneous distribution in the scaffolds.The XRD result shows that the crystallinity of nanometer hydroxyapatite is weak,conforms to the characteristics of the natural bone.FT-IR results reflect the join of PLA have reacted with the amino and carboxylto groups to enhance the stability of the substrate,which is consistent with the results of the compressive strength.In Vitro bioactive measurement in SBF demonstrated that the in situ formation of nano-HAP had good potential to direct crystallization.SD Rat osteoblast cells were used to set up in vitro evaluation model.The in vitro measurement showed the scaffolds had good bioactive.Although after PLA added into the scaffold reduced the hydrophily of the material,the cell culture results showed that it still kept a good biological activity.These results showed that the CS/Col/PLA/nHAP composite scaffold materials with good biocompatibility could promote the proliferation and differentiation of osteoblast.