The Electronic Structure,Bioactivity And Luminescence Of Calcium Phosphate Nanomaterials

Synthetic calcium inorganic phosphate(CaPi)nanomaterials have been widely used for biomedical applications because of their excellent osteogenesis characteristics,biodegradability and biocompatibility.In recent years,the development of nanotechnology facilitates the synthesis and optimization of various nanostructured materials.Nanostructured CaPi can be synthesized with desired compositions,crystal structures and morphologies,and their application in clinical research has been explored.Therefore,Understanding the fundamental properties of CaPi is of great importance to further optimize the performance of CaPi-based medical devices.In this thesis,CaPi nanostructures of different morphologies and compositions are synthesized,and their basic physicochemical properties are investigated.Synchrotron radiation X-ray spectroscopy is used to analyze the electronic structure and luminescence characteristics of CaPi by X-ray absorption near edge structure(XANES)and X-ray excited optical luminscence(XEOL).Biological property of CaPi is evaluated by co-culturing with osteoblasts.These results provide foundation for the development of novel CaPi-based biomaterials in the future..The thesis includes the following three parts:a.Electronic structure and biocompatibility of calcium phosphate coatings on Ti-based anodic nanotubes.Ti and Ti-6A1-4V are used as substrates and nanotubes are grown on their surfaces by anodization.CaPi coatings are then produced using biomimetic deposition.Multiple bioactive CaPi components such as hydroxyapatite,amorphous calcium phosphate,octacalcium phosphate and dicalcium phosphate dehydrate are identified in coatings.By analyzing the nucleation and crystallization process of the coatings,we find that the coating with more hydroxyapatite is beneficial for cell proliferation,while the one with more octacalcium phosphate is suitable for cell differentiation.b.Synthesis and bioactivity of amorphous calcium magnesium phosphate prosthesis nanomaterial.Amorphous calcium magnesium phosphate vesicles loaded simvastatin(ACMP/SIM)are obtained by coprecipitation method.These vesicles then undergo biomineralization and the morphology and compositions are monitored.We find the presence of SIM greatly enhances the osteogenesis property of ACMP.During the mineralization,SIM-loaded ACMP shows the high bioactivity that it would degrade first and then recrystallize into a higher crystalline phasec.Luminescence characteristics of europium-doped calcium phosphate nanomaterial.Eu-doped CaPi is obtained by co-precipitation method,and then calcined to become Eu3+ doped and Eu3+/Eu2+co-doped CaPi nanoparticles.By analyzing the luminescence characteristics and crystalline structure,we find the doping sites that Eu ions occupy in CaPi lattice are greatly influenced by calcination temperature and gas atmosphere.After studying the X-ray absorption edge and X-ray excited optical property of Eu3+/Eu2+co-doped CaPi nanomaterial,we find the doped Eu3+showed more stable luminescence than Eu2+ when excited under the same energy and duration.