Study On Biocompatibility,Osteogenesis And Degradation Of PCL-nHAC/Mg-Ca Alloy Composite In Vivo And In Vitro

ObjectiveThe biocompatibility and characterization of PCL-nHAC/Mg-Ca material were studied,and the material was implanted into the defect of rabbit skull to study the osteogenic property and degradation of the material.To explore its clinical application potential as a material for repairing bone defects,and to provide the basis for the next experimental study of bone stress area.Methods1.The PCL solution with the concentration of 0.10g/m L was prepared with dichloromethane,and then the nHAC powder and PCL solution were mixed under magnetic stirring(the mixture nHAC powder and PCL particles,weight ratio is 3:2).First fill the 0.5mm thick PCL-nHAC mixture layer at the bottom of the mold,then place the Mg-Ca alloy(6mm in diameter and 1mm in height)on the layer and in the center,then fill the mold with PCL-nHAC mixture,remove the residual chloroform by ultrasonic extraction,and dry.Finally,a PCL-nHAC/Mg-Ca alloy composite with a diameter of 8mm and a height of 2mm was formed.PCL-nHAC composites with the same size were prepared by the same method and used as control.The Mg-Ca alloy with 8mm diameter and high 2mm was also used as the control group after micro-arc oxidation.All materials are sterilized with 75% alcohol in sealed bags.2.The surface signs of the material were detected by scanning electron microscope(Scanning Electron Microscope,SEM)and Fourier transform infrared spectroscopy(Fourier Transform Infrared Spectrometer,FTIR).The PH change and degradation rate of the material were analyzed by in vitro immersion method.The porosity and pore size distribution of PCL-nHAC/Mg-Ca alloy composite materials were measured by mercury injection method.3.The effects of different materials and their extracts on the proliferation and adhesion behavior of mouse preosteoblasts(MC3T3-E1)were detected by CCK-8 method.4.The osteogenesis and degradation of the materials in the skull defect of rabbits were detected by Micro-CT.5.Histological samples of the implant site were collected,horizontal sections were made,and hematoxylin-eosin(H&E)Staining and observing bone formation around the implant under light microscope.Results1.CCK-8 results showed that all the materials had no cytotoxicity and could promote the proliferation of MC3T3-E1 cells.PCL-nHAC/Mg-Ca composites showed the best cell proliferation activity.At the same time,the results of direct co-culture SEM also showed that the number of adhesion growth on the surface of PCL-nHAC/Mg-Ca composites was more and the cells stretched obviously.2.In the simulated body fluid immersion experiment,compared with other control groups,PCL-nHAC/Mg-Ca composites showed the best corrosion resistance and structural stability.3.The Micro-CT test showed that the osteogenic property of PCL-nHAC/Mg-Ca composite was good,and the degradation rate was slower than that of mg-Ca alloy.4.Histological examination showed that the osteogenic properties of the experimental group were better than those of the other groups.ConclusionsPCL and nHAC as reinforcements can effectively reduce the erosion of body fluid on Mg-Ca matrix,and PCL-nHAC/Mg-Ca composites show good osteogenic properties.