Study On Preparation Of Metal Cationic Doped HA Bone Scaffolds By 3D Printing Extrusion Deposition

As one of the most important organs in human body,bone plays a vital role in human body.However,mass bone defects caused by tumor and trauma are still common orthopedic diseases in clinical medicine.The clinical treatment methods are still autologous bone flap transplantation with vascular pedicle and allograft bone transplantation,and the sources are very limited,the surgical trauma is large,the technical requirements are high,there are certain limitations.Therefore,the development of new bone graft alternatives has become the focus of researchers'exploration,and the birth of bone tissue engineering brings hope to researchers and patients.Natural bone is mainly composed of water,collagen,hydroxyapatite(Ca₁₀?PO₄?₆?OH?₂,HA),and HA is the main component.In addition,3D printing extrusion deposition technology has been widely used in the preparation of bone tissue engineering scaffolds due to its characteristics of accuracy,speed and diversification of functions.However,the HA in the natural bone is not pure HA,there are some zinc,magnesium,strontium,copper plasma.Based on the bionic concept,the bionic bone scaffold should simulate the special structure and main components of natural bone.The fabrication of metal cationic doped bionic bone scaffolds based on 3D printing extrusion deposition technology may become a highlight of bone tissue engineering.By simulating the HA component in natural bone tissue,Sr-HA and Cu-HA scaffolds are prepared by 3D printing extrusion deposition technology,ion exchange technology and sintering method,and the physical and chemical properties,antibacterial properties in vitro and biological properties in vitro were studied.The main study contents include the following aspects:1.Nanometer HA was used as raw material,sodium alginate as binder,and micron HA microspheres were prepared by 3D pneumatic printing,and their size,structure and in vitro biological properties were analyzed.The results show that the average diameter of HA microsphere is 1.819 ± 0.126 mm,ranging from 1.2 mm to 2.4 mm.After sintering,there were pores between grains of HA microspheres,the crystal structure does not change,and it has no toxic effect on rat mesenchymal stem cells?rMSCs?.2.Nanometer HA was also used as raw material and sodium alginate as binder.The Sr-HA and Cu-HA scaffolds were prepared by 3D printing extrusion deposition technology,ion exchange technology and sintering method,and the microstructure,mechanical properties,antibacterial properties in vitro and biological properties in vitro of Sr-HA and Cu-HA scaffolds were studied.The results show that Sr can replace the Ca site in HA and enter the HA lattice,while Cu can replace the OH site in HA.The crystallinity of HA modified by Sr and Cu is good.The best compressive strength of lOSr-HA and 5Cu-HA in the same element doped HA scaffolds is 5.12 MPa and 7.6 MPa,respectively.Cu-HA scaffolds in each group had antibacterial properties,which are enhanced with the increase of Cu content.The results of cell experiments show that Sr-HA scaffolds in each group had good biocompatibility,among which,10Sr-HA promoted the best proliferation of rMSCs.However,the performance of Cu-HA scaffolds is different from that of Sr-HA scaffolds,the 1Cu-HA and 5Cu-HA scaffolds showed good biocompatibility,while the 10Cu-HA and 15Cu-HA scaffolds showed strong toxicity.In summary,the 3D-printed 10Sr-H scaffold in this study has good mechanical properties and the best effect on promoting the proliferation of rMSCs in vitro.And the preparation of 1 Cu-HA and 5 Cu-HA scaffolds also show good mechanical properties,not only has strong antibacterial properties,but also has good biocompatibility.All three scaffolds are potential materials for repairing bone defects and have a certain application prospect in bone tissue engineering.