| Objectives Nowadays,biocomposite materials have become the main materials for repairing bone defects.Among them,nano-hydroxyapatite / polyscaffold materials have become a research hotspot.As the research progresses,the shortage of composite scaffold materials is gradually exposed.The main reason is that the self-aggregation of nanohydroxyapatite in the organic matrix affects the overall performance of the composite material.To solve this problem,surfactant-polyethylene glycol(PEG)was used to modify the surface of nano-hydroxyapatite(n-HA)to improve the nano-hydroxyapatite / polylactic acid composite scaffold The porosity and mechanical strength of the material.Methods Experiment 1 Weigh 7 parts(5g)of nano-hydroxyapatite powder and add200 ml of deionized water to mix well.Add polyethylene glycol according to the mass ratio of n-HA(1%,2%,3%,4%,5%,6%,7%).Stir at a constant speed with a magnetic stirrer for 4 hours at a constant temperature to obtain a milky white solution.Discard the supernatant repeatedly until the supernatant is translucent.Vacuum freeze-drying for 10 h to obtain modified nano-hydroxyapatite powder,which is denoted as PEG-n-HA(1,2,3,4,5,6,7)sealed and stored for future use.The modified nano-hydroxyapatite was detected by Fourier infrared analysis,X-ray diffractometer,zate potential particle size analyzer,scanning electron microscope,cytotoxicity detection and other methods.All data were statistically analyzed by spss17.0 statistical software,and the difference of p <0.05 was statistically significant.Experiment 2 Use the PEG-n-HA(5%)powder and n-HA powder obtained in Experiment 1 and polylactic acid in proportion to the organic porogen(dichloromethane /1,4-dioxane).The composite scaffold material was prepared by vacuum freeze-drying method.The two before and after modification were divided into 4 groups according to the composite scaffold material and the amount of nano-hydroxyapatite added(5%,10%,15%,20%).The surface structure,porosity,compressive strength and cytotoxicity of the two groups of materials were tested and analyzed.All data were statistically analyzed by spss17.0 statistical software,and the difference of p <0.05 was statistically significant.Results xperiment 1 1)The result of FTIR analysis showed that the absorption peak of-CH2 group in the PEG surfactant was newly added at 2925.90 cm-1 on the PEG-n-HA powder spectrum.2)XRD results show that the crystallinity and phase of PEG-n-HA have not changed after modification.3)The zate potential particle size analysis shows that the distribution range of n-HA particles in solution is within 150?1000nm,and the distribution range is too wide,which is not conducive to the uniform distribution of n-HA in organic solvents.The particle size distribution of 1%?4%,6%?7% modified ratio of PEG-n-HA is generally between 200?750nm.The 5% ratio of PEG-n-HA particles is more evenly distributed around 100 nm.4)SEM observation magnifies 500 times when n-HA aggregates into large particles,and PEG-n-HA is evenly distributed into smaller particles.When magnified to 5 × 104 times,it can be observed that the modified group n-HA particles are spherical After aggregation,the modified group can clearly see the PEG-n-HA particles with a shape like a mallet and a length of about 100 nm.5)The test results of MTT method show that the surface modification of nano-hydroxyapatite by PEG does not change the biocompatibility of the material itself.All data were statistically analyzed using SPSS17.0 statistical software,P <0.05 was statistically significant.Experiment 2 n-HA / PLA and PEG-n-HA / PLA composite scaffold materialsprepared by vacuum freeze-drying method.1)Scanning electron microscope observation found that n-HA / PLA porous composite scaffold material can observe agglomeration of n-HA,causing some large pores to reduce or block the pore size,the number of small pores on the pore wall is small,and the connection between the voids Sexuality is reduced.The phenomenon of uniform distribution and agglomeration of nanomaterials in PEG-n-HA /PLA porous composite scaffold materials is rare.2)Porosity test results: The difference of the porosity of the PEG-n-HA/PLA composite scaffold between(83.465 ±1.633)%?(73.516 ± 1.823)%(P<0.05)was statistically significant.3)The compressive strength test results show that the average compressive strength of the PEG-n-HA / PLA composite scaffold material is(3.699±0.033)MPa ?(4.154±0.007)MPa(P<0.05)the difference is statistically significant.4)The cytotoxicity test showed that the composite scaffold materials of the n-HA/PLA group and the PEG-n-HA/PLA group had no cytotoxicity,which met the basic conditions of fibroblast proliferation.All data were statistically analyzed using SPSS17.0 statistical software,P<0.05 was statistically significant.Conclusions 1)The 5%-modified PEG-n-HA has the best dispersion in organic solvents and the smallest particle size.2)In the experiment,the porosity and compressive strength of the PEG-n-HA / PLA composite scaffold material prepared by vacuum freeze-drying method were improved,and the biocompatibility was good.Figure8;Table6;Reference 134... |
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