Hard And Soft Template Method Preparation Of Micro/nano Hydroxyapatite (HA) With Hierarchically And Biological Activity Research

Human bone and teeth are a kind of very important biological minerals,which are mainly composed of organic matrix and hydroxyapatite(HA).HA has excellent biocompatibility and biological activity,so it has a wide range of applications in the field of biomedicine and has attracted extensive and persistent attention from researchers.As the growing acknowledgement of hydroxyapatite research,micro/nano structured HA materials with hierarchical have been the focus of research because of their special surface structure which can enhance the adsorption properties and promote cell growth.However,there are still many problems,for example,it is impossible to accurately control the preparation of micro/nano structured HA with hierarchical and HA crystallinity,and the problem of biocompatibility of HA materials.Therefore,on the basis of existing research,through further screening and optimization of the template,so as to realize the accurate control of micro/nano structured HA with hierarchical to enhance the surface cell adhesion and growth ability has important practical significance.Based on the above ideas,we chose self-made calcium carbonate(Ca CO3)microspheres as hard template and modified articular cartilage membrane(ACM)as soft template to investigate these templates how to control the preparation of micro/nano structured HA with hierarchical,and further study the properties of HA materials.The main contents are as follows:(1)Hard template method: Monodispersed vaterite Ca CO3 microspheres with regular morphology are synthesized by a precipitation method in the presence of sodium carboxyl methylcellulose,and then used as a hard template to induce the formation of monodisperse and homogeneous micro/nano structured HA with hierarchical microspheres in a hydrothermal reaction.By regulating reaction temperature and amount of surfactant sodiumdodecyl benzene sulfonate,the secondary nano building blocks of HA microspheres can be accurately controlled.At the same time,based on XRD,FTIR and HRTEM characterizations,the mechanism of under different temperature and different SDBS concentration is proposed.We believe that the growth of HA crystals with different crystal faces is different under different temperature or different concentration of SDBS,which can control the morphology of HA crystal.The results show that the surface of HA microspheres is composed of HA nanorods and nanoplates.The average particle size of HA microspheres is about 7-8 ?m,which has the advantages of uniform size,good dispersion and large specific surface area.After the analysis of drug loading and release of HA microspheres,it is a good drug carrier material.In vitro cell experiments show that HA microspheres can promote the adhesion and proliferation of human osteosarcoma cells(MG-63)and have significantly high cell viability.Moreover,the HA microspheres with nanoplates promoted cell reproduction better than those with nanorods.(2)Soft template method: Used modified pig bone articular cartilage membrane(ACM)as soft template,a sponge-like and micro/nano structured HA with hierarchical is self-assembly synthesized in simulated body fluid.Its crystallographic structure and composition are studied by SEM,XRD,FTIR and TEM,which shows that the synthesized sample is carbonated HA crystals and the three-dimensional interconnected sponge-like structure is assembled by massive nano HA plates.In view of the composition and structure similarity of as-prepared sampleand cancellous bone,their density,porosity and specific surface are compared.The results indicate that the sponge-like HA has much higherdensity,porosity and specific surface in addition to the same structure and composition.Experimental results of cell culture show that the sponge-like HA can highly promote the adhesion and proliferation of MG-63 cells,and have good bioactivity.The results of this study will provide a method for the precise control of micro/nano structured HA with hierarchical and the construction of the new micro/nano and hierarchical structure,and provide a useful reference for the study of the effects of HA nano structure units on their biological activities.