Study On Mineralization Performance And Mechanism Of Several Typical Ceramic Materials

The process of biomineralization has many important implications for biomineralization and ecological environment.Most of the existing studies evaluate the biological properties of biomaterials through in vitro mineralization experiments,and the research on the mineralization properties and mechanism of biomaterials is rarely reported.In this paper,by studying the mineralization behavior of biologically active calcium silicate ceramics and calcium-phosphorus based ceramics（HA andβ-TCP ceramics）,biologically inert alumina ceramics and alumina-based ceramics（Ca₆,Al PO₄ and 3Al₂O₃ 2Si O₂）in different mineralization media,the factors affecting the biomineralization of materials were explored,so as to reveal the mechanism of material mineralization in vitro.Calcium silicate ceramics have excellent mineralization properties and degradability,which can quickly induce the deposition of hydroxyapatite in simulated body fluids.Higher ion concentration of SBF has the function of the accelerating mineralization process.In this study,the mineralization mechanism of calcium silicate ceramics was revealed by exploring the mineralization behavior of calcium silicate ceramics in x1 SBF and x5 SBF.The results show that the release of calcium silicate ions and the formation of new calcium silicate layer（≡Si OCa⁺）are the key factors to induce the mineralization of calcium silicate ceramics.For the calcium-phosphorus based ceramics HA and TCP ceramics,have poor degradability,which is not through the deposition of bone-like hydroxyapatite and bone on the surface of the implant,but benefits from its similar components to natural bone.In this paper,calcium–phosphorus-based ceramics were mineralized in x1 SBF and modified SBF.The results showed that in the modified SBF with F-and higher phosphate ion concentration,the HA ceramic crystal grew preferentially towards the（002）crystal plane to produce the preferentially HA with higher biological activity and osseous properties.On the surface ofβ-TCP ceramics,fluorapatite with low Ksp was deposited preferentially on the surface ofβ-TCP ceramics,which provided a large number of nucleation sites for the later deposition of hydroxyapatite.The high concentration of phosphate ions in the solution also promoted the formation and deposition of hydroxyapatite to some extent.The results of biological experiments of bioactive ceramics show that the mineralized materials have better biological activity and bone-promoting propertiesIn this study,the mineralization behavior of alumina ceramics in x1 SBF,x5 SBF,FBS and modified SBF was explored based on the study of the biomineralization performance of bio-active materials.It was found that in the modified SBF,the alumina ceramics did not release ions itself,but provided a large number of nucleation sites for the later deposition of hydroxyapatite through the preferential deposition of fluoroapatite.Under the induction of high concentration of phosphate ions,apatite deposited in large quantities in the later mineralization period.The results of in vitro biological experiments showed that the mineralized alumina ceramics had better biological activity and osteogenic properties.The results show that calcium hexaaluminate has better mineralization ability in x1 SBF.In CA₆,aluminum exists in the form of Al³⁺,so in the early stage of the mineralization of CA₆ceramics,large amounts of calcium and aluminum ions released from the surface,created more cationic vacancy on the surface,the phosphate ions in SBF deposited on the surface due to the electrostatic reaction,As for aluminum ceramic material containing phosphorus conponent aluminum phosphate ceramic（Al PO₄ ceramic）and aluminum ceramic materials containing silicon component aluminum silicate ceramic（3Al₂O₃ 2Si O₂）,because of it does not release the ions in simulated body fluid itself,so there are no suitable nucleation sites on the surface that achieve hydroxyl apatite deposit.The results of in vitro biological experiments of calcium hexaaluminate ceramics show that the mineralized calcium hexaaluminate ceramics have better biological activity and osteogenesis properties.