| Objective: In this study,biodegradable biomedical materials polylactic acid(PLA)and allogeneic microparticle bone meal were used as raw materials to prepare for a new-type bone meal/polylactic acid composite wire for the fused deposition 3D printer.The 3D printing method was used to construct the bone tissue engineering scaffolds for exploring the preliminary preparation technology and analyzing physicochemical and mechanical properties.The rabbit adipose stromal cells were extracted as seed cells to provide the theoretical basis for the further experiment of cytotoxicity detection of scaffold cells.Methods: The rabbit defatted protein bone were prepared by ethanol degreasing and hydrogen peroxide deproteinization,and it were crushed by ball milling and vacuum freeze-dried.Mix 5% and 10% bone mass with PLA powders,respectively,and put into a screw extruder to extrude the 3D printed wires.Radial defect model was designed by computer-aided design of the tubular bone tissue engineering scaffold structure,and generated 3D printer recognizable STL file,using the prepared 3D printing wire,in a fused deposition 3D printer,the nozzle temperature of 210 ° C,print bone Tissue engineering scaffolds.The diameter of 3D printed wire was measured.The microstructure of the bone tissue engineering scaffold was observed by scanning electron microscopy.X-ray diffraction was used to analyze the phase change of the raw material powder,wire and stent.The compressive strength of the universal testing machine was measured.The Vickers hardness Instrument hardness testing,drainage method for scaffold porosity detection,the weight of the stent in vitro degradation.Taken rabbit fat block was cut by tissue block method to extract primary rabbit adipose stromal cells,passage to the fourth generation,CCK8 test scaffold extract on cell toxicity.Rabbit skimmed rabbit skins were vacuum-freeze-dried by skimmed rabbit skimmed protein and then homogenized by ball milling with 5%,10% and PLA powders,respectively,and put into a screw extruder to extrude the 3D printed wires.Radial defect model was designed by computer-aided design of the tubular bone tissue engineering scaffold structure,and generated 3D printer recognizable STL file,using the prepared 3D printing wire,in a fused deposition 3D printer,the nozzle temperature of 210 ° C,print bone Tissue engineering scaffolds.The diameter of 3D printed wire was measured.The microstructure of the bone tissue engineering scaffold was observed by scanning electron microscopy.X-ray diffraction was used to analyze the phase change of the raw material powder,wire and stent.The compressive strength of the universal testing machine was measured.The Vickers hardness Instrument hardness testing,weight method for scaffold porosity detection,the weight of the stent in vitro degradation.Taken rabbit fat block in the inguinal region was cut by tissue block method to extract primary rabbit adipose stromal cells,passage to the fourth generation,CCK8 test scaffold extract on cell toxicity.Results: Microparticle bone meal/polylactic acid 3D printing wires and bone tissue engineering scaffolds with 5% and 10% of bone meal contents were successfully prepared.Majorities of crest changes in X-ray diffraction patterns of bone meal PLA mixed powders,wires and scaffolds were not obvious.By making a comparison with the standard HA X-ray diffraction patterns,there was the characteristic diffraction peak of hydroxyapatite HA in natural bone shown in the bone meal polylactic acid scaffold XRD pattern(2?=25.9°and 32.2°).5% of bone meal PLA scaffold porosity was about 31.3% and compressive strength was 60.33 Mpa.And those of 10% of bone meal PLA scaffold porosity were about32.9% and 38.51 Mpa,respectively.Scaffold extract liquid was basically consistent with the cell proliferation of the medium control group.There was no statistical significance in absorbance value between extract liquid group and medium control group of each time point.The degradable residual mass percent of 6 months in vitro was 93.8%.Conclusion:(1)It is a feasible method to construct bone tissue engineering scaffolds by preparing bone meal PLA printing wires in advance and using the fused deposition 3D printing technology.(2)The scaffold strength ranges from cartilage to cortical bone.And the porosity basically meets the design requirements.The bone meal PLA scaffold extract liquid has no obvious cytotoxicity in the cytotoxicity test.It can be used for bone tissue engineering study.The animal experiment is further conducted to study pro-ossification. |
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