Biomimetic Synthesis And Performance Characterization Of Bamboo Rat Enamel-like Fe-containing Hydroxyapatite

The inorganic phase of most mammals’ teeth,including human,is hydroxyapatite（HA）.However,the inherent brittleness and poor mechanical properties of HA ceramics severely limits its application as dental restorative material.Meanwhile,the microstructure,crystal structure and doping modification of nano-HA particle needs to be further researched.Available researches have shown that bamboo rat enamel shows higher hardness,better wear resistance and acid corrosion resistance than that of human enamel.In this study,natural enamel-like hydroxyapatite were synthesized through biomimetic synthesis to improve its overall performance and expand its application in dental restorative materials.In this study,the surface red enamel of bamboo rat incisor was selected as bionic subject.Detailed microstructure and composition information of hydroxyapatite in bamboo rat incisor were characterized using a variety of analysis and testing methods.On this basis,bamboo rat enamel-like Fe-containing hydroxyapatite（Fe-HA）were prepared by ultrasonic assisted microwave hydrothermal method with Ca（NO3）2·4（H₂O）,Fe（NO3）3 9（H₂O）and（NH4）2HPO4 as raw materials.The effects of Fe content on the phase composition,crystal structure and microstructure of Fe-HA were investigated.The micro-hardness,corrosion resistance,tribological properties and antibacterial properties of the prepared Fe-HA composite bioceramics were systematically studied.（1）The main inorganic phase in the surface red enamel of bamboo rat incisor is Fe-containing hydroxyapatite and the relative content of Fe is about 6.08 wt%.The Fe-containing hydroxyapatite crystal has a rod-like microstructure with a length of about 100 nm and diameter about 15 nm,and its preferable growth face is（002）.（2）Calcium-deficient Fe-HA nanoparticles with uniform grain size and low crystallinity were prepared by ultrasonic assisted microwave hydrothermal synthesis,which is similar to the structure of bamboo enamel HA.The Fe content has a great influence on the morphology and crystal structure of Fe-HA.When the Fe content is 1.5 wt%,the obtained Fe-HA has the highest crystallinity,which shows a short rod-like microstructure with the length about 100 nn and diameter about 15 mm.（3）The results of reciprocating sliding wear test,soaking test and bacterial test indicated that Fe1.5 wt%-HA bioceramics exhibits better mechanical properties（e.g.hardness and wear resistance）,acid corrosion resistance and anti-bacterial properties than that of the pure HA ceramics.