Research On Preparation Of Hydroxyapatite/Polycaprolactone Bone Scaffold By Low Temperature 3D Printing Extrusion Deposition

In this study,we selected green and low-toxic dimethyl carbonate(DMC)as the solvent for the organic polymer polycaprolactone(PCL),and introduced nano-hydroxyapatite(HA)with good bone conductivity.Use Low temperature deposition manufacturing(LDM)to prepare a new three-dimensional(3D)porous tissue engineering bone scaffold.During the preparation process of thescaffold,a multi-nozzle low-temperature 3D printer based on pneumatic extrusion was designed and built,and the equipment was used to successfully prepare thescaffold blank with3 D geometry and the required macroporous structure,and then thescaffold blank was frozen During the drying process,due to the phase separation,the fabricated scaffold has a microporous structure.Characterize thescaffold by scanning electron microscope(SEM),X-ray diffractometer(XRD),Fourier infrared spectrometer(FT-IR),universal testing machine,differential scanning calorimeter(DSC)and contact angle tester.The biocompatibility of the scaffold was tested by in vitro cell culture experiments.The results showed that: using DMC as solvent,there were micropores on the surface of PCL scaffold prepared by LDM technology.The micropores were between1 ? 10 ? m in diameter,and the cross-section of the scaffolds was fishbone,which had good mechanical properties.The average diameter of macropores of 10%wt-HA/ PCL and 20%wt-HA / PC composite scaffolds was 421.4 ± 21.3 ? m,and there were also micropores on the surface of the scaffolds.At the same time,the HA aggregation of 20%wt-HA / PCL composite scaffold was obvious;The results of XRD and FT-IR showed that DMC did not change the crystal structure of PCL,and all DMC volatilized after freeze-drying.HA and PCL coexisted well,and there was no obvious chemical interaction between them,which resulted in the lower tensile property of HA / PCL composite scaffold than PCL scaffold;DSC results showed that the addition of HA increased the cooling crystallization temperature and decreased the melting temperature of the scaffold;Contact angle test showed that the addition of HA increased the hydrophilicity of the scaffold.Mouse bone marrow mesenchymal stem cells(MSCs)were seeded on scaffolds for 1,3 and 7 days.The living / dead cell staining(AM / PI)was performed on the scaffold extract cell complex on the first day.The results showed that the addition of HA improved the cell proliferation.CCK-8method was used to detect the cell proliferation on 1,3 and 7 days.The results showed that the more evenly dispersed HA was,the more promoted the cell proliferation.In conclusion,it showed that the HA/PCL composite porous scaffold prepared by using the green low-toxic solvent DMC and the low temperature 3D printing extrusion deposition manufacturing technology has broad prospects in bone tissue engineering.