Synthesis Of Functional Calcium Phosphate-based Nanocomposites And Their Biomedical Applications

As the improvement of living standards and the development of technologies,new smart multi-functional biomaterials,with the integration of anti-bacteria,imaging,cancer diagnosis and photothermal/photoacoustic treatment,targeted drug delivery,tissiue repair and regeneration,is getting popular.Pure calcium phosphate materials which exhibit high biocompatibility,bioactivity and biodegradation can no longer meet the high requirements because of the single component and functions.Herin,novel multi-functional calcium phosphate based composites could be developed by the addition of functional components while the advantages of CaPs could be maintained.The nanocomposites are promising in different biomedical applications.In this dissertation,we prepared various functional calcium phosphate based composites by doping metal ions or compositin with polymer.In addition,their physicochemical properties have been characterized and we further investigate their biomedical applications in caries resteration,bone tissiu repair,cancer diagnosis and treatment.The main research results are shown as follows:1)Synthesis,properties and applications of the calcium phosphate based nanocomposites by the hybridizing with functional metal ionsThe gluey silver–calcium phosphate(GSCP)composites have been synthesized by the addition of silver ions using the rapid microwave-assisted solvothermal method with ATP as the phosphorous source and stabilizer.The as-prepared GSCP composite is an organic–inorganic hybrid,and Ag ions display a significant influence on the formation of GSCP by interacting with adenosine triphosphate biomolecules.The as-prepared GSCP composite shows good antibacterial properties,in addition,it exhibits a great effect on sheltering dentinal canaliculi and improving the remineralization of dentine in the simulated saliva.The as-prepared GSCP composite is promising for various applications such as oral healthcare,especially,remineralization of dentine,and antibacterial applications.The ferrous ion doped–calcium phosphate(FCP)composites have been synthesized by the addition of ferrous ions using the rapid microwave-assisted solvothermal method with ATP as the phosphorous source and stabilizer.The as-prepared FCP composite,which is consisted of porous nanoparticles,exibits a pH-dependence catalytic behavior and is promising in the application of cancer starving therapy as a cell-selective biomaterial.The bismuth doped–calcium phosphate(RBCP)composites have been synthesized by the addition of bismuth ions using the rapid microwave-assisted solvothermal method with ATP as the phosphorous source and stabilizer,followed by a reduction reaction.The as-prepared RBCP composite is consisted of nanoparticles with irregular morphologies and has a broad absorbance from ultraviolet to infrared wavelength.In addition,under the irradiation of 808 nm NIR laser,it shows an excellent photothermal efficiency,which is potential in cancer photothermal therapy.2)Synthesis,properties and application of the ultralong HAP nanowires/glycerol citrate polyester nanocompositeSpecifically,the ultralong HAP nanowires are pressed into a disk to form a porous ‘‘skeleton” of the nanocomposite;then the disk is immersed in a precursor liquid containing citric acid and glycerol,and the ‘‘muscle” is formed after the condensation reaction between glycerol and citric acid at an elevated temperature.The porous ‘‘skeleton” made of ultralong HAP nanowires has micro-/nano-sized pores to enable the precursor liquid permeate into it facilely,which can ensure the formation of the homogeneous phase of the nanocomposite.Moreover,ultralong HAP nanowires overlap,interweave and cross with each other to reinforce the mechanical properties of the nanocomposite.In addition,ultralong HAP nanowires can neutralize the acidity of citric acid formed by the degradation of glycerol citrate polyester to stabilize the pH value of the microenvironment.