| Three-dimensional scaffold is the core of the establishment cells and organisms in bone tissue engineering,In order to make it more suitable for clinical bone repair needs,We had preliminary studied biological activity of op-HA and PLGA in degradation characteristics of the combination of polymer materials to improve the biocompatibility and osteoinductive capacity. With the development of technology, conductive polymer is currently being further studied.They have unique electrochemical and physical properties and the potential use of biological medicine including in biosensors,neural probes,drug release regulator,initiator and self-oxidants. Copolymer were consisted of Aniline oligomer and the aliphatic polyester.They were characterized by conductivity,biodegradability,biocompatibility.In this paper,the conductive material with the PAP and the op-HA composites were prepared by blending PLGA.In two and three dimensional structure was characterized by instrument testing.cell culture, animal experiments.By means of its physical and chemical properties,mechanical properties,biocompatibility and evaluation of bone ability can observe the content of materials with different conductivity in tissue engineering feasibility study. Proportion of the PAP to find the best content, provide the basis for clinical application.â… ,Preparation and Characterization of MaterialsWe adopted solution method.Firstly, aniline oligomer (AP) and polylactic acid (PLA) block copolymer (PAP) and op-HA/PLGA were compounded by a certain percentage.Then.conducting polymers PAP/op-HA/PLGA electrochemical properties can be tested by a UV spectrophotometer,cyclic voltammetry and electrochemical analyzer; Thermal stability were tested by TGA,DSC; The membrane morphology were observed by ESEM and FAM; The contact angle were tested to observe hydrophilic,The results showed that PAP/op-HA/PLGA has electrochemical properties. With the introduce of PAP material, the surface is more flat, they have good thermal stability,hydrophilicity.The requirements can be needed for tissue engineering scaffold. â…¡,Cell proliferation, adhesion and osteogenic activityThe cells were cultured on the membrane material.At different time points by using fluorescein isothiocyanate (FITC) staining of osteoblasts. cell's form and quantity was observed by fluorescence microscope, a single cell area percentage was analysized by NIH Image J software; proliferation of osteoblasts in polymer surface was tested by MTT; Collagen-â… ,BMP-2 and Osteonectin expression were detected by RT-PCR method; ALP detection kit for determination of ALP activity. The results showed that low content of PAP/op-HA/PLGA osteoblast adhesion and proliferation was enhanced. Therefore,It promotes bone formation.â…¢,Preparation and evaluation of scaffoldsScaffolds were prepared by freeze-drying method. Solvent is 1.4-dioxane. Scaffolds with different PAP content were observed by ESEM,porosity testing, mechanical testing, cytology evaluation.The results show that with increasing concentration of conductive material PAP. the color of the scaffolds gradually were deepened, surface hardness decreased gradually. Pore size of materials were metted to tissue engineering, porosity increased with the content of PAP,low concent of conductive scaffolds have excellent mechanical properties and promote cell adhesion and penetration.â…£,Vivo experimentsThe scaffolds was implanted into Rabbit back muscles, then drawn at different time points. General observation at 1m,3m,5m, the gradual degradation were observed in PLGA group,However,containing PAP, op-HA particles, the hardness of the scaffolds increased,It remains roughly outline, the scaffolds changes in muscle tissue were observed by ESEM, X-ray, histological. The results showed that the scaffolds were connected with muscle tightly, the osteogenic capability gradually were enhanced. We believe that the scaffolds have good biocompatibility with muscle tissue in the body. As the introduce of op-HA and PAP,the scaffolds showed good ability of bone formation.â…¤,Experimental study of rabbit bone defect repai under electrical stimulationEstablishment of bone defect model,under the effect of pulses electrical stimulation.we evaluate the bone repair capacity. The middle of rabbit radius bone 20mm defects model,different content of PAP/op-HA/PLGA scaffolds were implanted in the bone defect,in 4 w and 1Ow, the amount of bone formation detected by X-rays to evaluate the ability of bone repair. The results showed that after 4w, defection of op-HA/PLGA,0.1%PAP/op-HA/PLGA,1%PAP/op-HA/PLGA can be seen clearly in the growth of callus,fracture line blurred.the initial connection of bone formatio,10%PAP/op-HA/PLGA cnductive material relative to the low concentration have poor bone healing; after 10 weeks,0.1%PAP/op-HA/PLGA.1%PAP/op-HA/ PLGA group generated a lot of callus.These can be seen in X-rays.The defect replacement by new bone,callus can be seen crawling along the ulnar growth, and the other end of the fusion of bone callus and the ends was connected. Experimental results show that low content of PAP conductive scaffolds can strenghten bone repair and reconstruction, show good prospects.Therefore,Electrical stimulation significantly accelerated fracture healing.â…¥,Experimental study of sheep tibial defectsWe observe bone healing in a large animal bone defects 25mm of sheep tibia.With the general assessment, At the different time points, the amount of bone formation was detected by X-rays to evaluate the ability of bone repair materials. Bone formation was observed by CT.The results showed that PAP's scaffolds enhanced bone repair.One percent of PAP bone scaffold bone repair ability is superior than ten percent of that.Conclusion:Low content of electroactive polymer nano-composite bone repair PAP/op-HA/PLGA have good biocompatibility,osteoblast adhesion,proliferation and osteogenic gene expression of related to bone repair,by the bone defect experiment and the role of the pulse electrical stimulation,the material reflects a good performance.
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