Preparation And Biological Properties Of Magnetic Hydroxyapatite/chitosan Three-dimensional Porous Scaffold

Bone repair materials havedrawn great attention in the research of biomedical materials.Therefore,a novel biomaterial needs to be created to treat bone defects caused by trauma,surgical resection and other situations.Three-dimensional porous scaffolds have become a hotspot in bone repair materials due to their good biocompatibility,mechanical properties,three-dimensional structure,high porosity and suitable pore size.The magnetic field can produce magnetic force on bone tissue,promoting osteoblast proliferation andbone regeneration.The permanent magnet material M-type ferrite has relative highercoercivity,saturation magnetization and remanence,which is not easy to demagnetize and have certain biocompatibility.Hydroxyapatite(HAP)and chitosan(CS)have good biocompatibility and bioactivity,and are widely used in bone tissue engineering.In this study,the magnetic hydroxyapatite/chitosan three-dimensional scaffold(SHCP,STCP)was successfully prepared by combining the permanent magnet materials M-type ferrite and HAP and CS by allegation,in situ transformation and freeze-drying.The microstructure,mechanical properties,pore size distribution and magnetic properties of magnetic hydroxyapatite / chitosan three-dimensional porous scaffolds were analyzed by means of FESEM,EDS,XRD,FTIR,VSM,PMI and electronic universal testing machine.The biocompatibility and osteoinductive capability tests of the SHCP and STCP were conducted using human bone marrow stromal cells(hBMSCs)as cell models.The magnetic hydroxyapatite/chitosan three-dimensional porous scaffold(SHCP)was prepared by mixing method and the freeze-drying technique.The magnetic scaffold has interconnected three-dimensional macropores with the pore size of 80?m-300?m,the porosity of 90% and has good mechanical properties with the maximum stress of 0.51MPa±0.01 MPa.While the addition of the magnetic particles(M-type ferrite)did not change the three-dimensional structure of the material,and the magnetic scaffold(SHCP)has good magnetic properties.The magnetic hydroxyapatite/chitosan three-dimensional porous scaffold(STCP)was prepared byin-situ transformation method and freeze-drying technique.The STCPpossessed three-dimensional porous structure with a macropore size of 80?m-240?m and a porosity of 89%.The CaCO3 particles were completely converted into flaky cluster-like microspheres with thickness of 50-100 nm,a pore size between 200 nm and 1?m.The addition of the magnetic particles M-type ferrite did not change the three-dimensional structure of the material,and the STCP had good magnetic properties.The results of hBMSCs showed that SHCP and STCP had good biocompatibility and no toxicity to the cells,andthe introduction of magnetic field is conductive to cell migration,differentiation and proliferation.In addition,the results of osteogenic differentiation showed that SHCP and STCP could promote the differentiation of osteoblasts and had better osteogenic differentiation ability.The introduction of magnetic field made materials had better osteoinductiveproperties,so that SHCP and STCP could be considered as substituted materials in orthopedicsand had great potential value in the application.