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Mechanical Stability And Distribution Of Regenerated Bone Tissue In Three-dimensional Bionic Bone Tissue Engineering Scaffolds

Posted on:2024-08-15Degree:MasterType:Thesis
Country:ChinaCandidate:P X ZhiFull Text:PDF
GTID:2531306932975859Subject:Surgery
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Objective: The aim of this study is to compare a novel truncated cone 3D scaffold with a traditional cylindrical scaffold through finite element analysis,and to study their respective settlement after being subjected to stress within the bone tissue through simulation experiments to select a 3D scaffold with good mechanical stability for application in animal experiments.The animal test aims to study the growth of cells in the titanium 3D bionic bone tissue engineering scaffold,and the distribution trend of its growth,to provide an improved idea for better use of the titanium 3D bionic bone tissue engineering scaffold in the treatment of osteoarthritis.Methods: The parameters of the conventional cylindrical and new truncated cone Ti-6Al-4V alloy bone tissue engineering scaffolds prepared by the EOS M270 printer through 3D printing technology were first collected and imported into Ansys 2021 R1 software for modelling,and then finite element analysis was performed to compare the settlement of the new truncated cone 3D scaffold and the conventional cylindrical scaffold when they were implanted in human bone tissue under stress.The results of the simulations showed that the new truncated cone 3D scaffold could be used for the implantation of bone tissue.The results of the simulations showed that the new truncated cone bone tissue engineering scaffold had better mechanical stability,so the truncated cone scaffold was used to continue the study of cell growth and distribution trends.A truncated cone PLA-PLGA-Titanium(Ti)3D bionic scaffold was fabricated using the Direct Metal Laser Sintering(DMLS)method with an EOS M270 3D printer.Five healthy adult sheep,aged 3.4-4.9 years,with an average age of(4.1±0.7)years,weighing 30.6-53.1 kg,with an average weight of(42.8±0.7)kg,were used.Select the load-bearing area of the left knee femoral condyle of 5sheep as the implantation site for the scaffold.Drill a hole with a depth of10 mm using a 0.7mm Kirschner wire in the load-bearing area of the inner condyle,and then use a truncated cone drill bit with the same size as the scaffold prepared in 2.1.1 of this article to guide the hole into the bone according to the Kirschner wire finger,with a depth of 10 mm.After taking out the Kirschner wire and drill bit,flush the bone defect with a large amount of normal saline,then implant a three-dimensional bionic scaffold(prepared in2.1.1 of this article)into the hole,suture the articular capsule,and suture the incision layer by layer.After surgery,raise each sheep separately.After continuous observation for 12 weeks,the surgery was performed again.The truncated three-dimensional biomimetic stent was removed from the implant site using a 9mm cylindrical hollow drill bit.After the surgery,the sheep were euthanized under anesthesia.The stent specimen was cut at 1.30 mm intervals in a vertical direction with a micro cutter,making a total of 7 slices.The sections were scanned through a Niko XT H 225 CT machine to obtain 2D images and imported into a MATLAB image analysis program,which divided the scaffold into 1 to 4 layers in the vertical direction from top to bottom and 1 to 6 columns in the horizontal direction from left to right,for a total of 24 regions,and sequentially quantified the regenerated bone tissue within these 24 regions using MATLAB.Among these 24 areas,the 12 areas in direct contact with the host bone tissue were defined as marginal areas,the 4 areas in the central area of the scaffold furthest from the contact surface were defined as central areas,and the8 areas between the central and marginal areas were defined as intermediate areas,and the differences in the percentage of regenerated bone tissue in the marginal,intermediate and central areas were analyzed using SPSS 26.0statistical software.Results: Using finite element analysis,the maximum and minimum values of Von’s stress,equivalent stress and deformation were obtained for the cylindrical and truncated cone scaffolds.Twelve weeks after implantation,the results showed that there was already new bone tissue growth inside the truncated cone scaffold,and the difference in the percentage of cell growth in the marginal,intermediate and central zones was statistically significant(F=9.290,P=0.001),with the percentage of bone cell growth in the marginal zone being higher than that in the intermediate and central zones,and this difference was statistically significant(P=0.000,P=0.031).The percentage of osteoblast growth in the middle zone was higher than that in the central zone,and this difference was statistically significant(P=0.037).Conclusion: Compared to conventional cylindrical scaffolds,the truncated cone 3D scaffold has better mechanical stability and less settlement after stress.After 12 weeks of implantation of the truncated titanium 3D bionic bone tissue engineering scaffold into sheep,new bone tissue growth was observed in the scaffold,with the greatest distribution at the margins and a gradual decrease in regenerated bone tissue from the margins to the centre of the scaffold.
Keywords/Search Tags:bone tissue engineering, three-dimensional bionic scaffolds, mechanical stability, bone regeneration, three-dimensional mesh structure
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