Studies On Preparation Technology And Nano Characteristics Of Nanoscaled Hydroxyapatite

Hydroxyapatite has been widely used in clinic due to its good biocompatibility and osteoconductivity derived from the most similar composition and crystal structure with mineral in bone. However, the artificially synthesized HAP materials for the repairing of bone defects are greatly restricted to apply in the load-bearing situation because of its lower mechanical properties compared with natural bone. Moreover, the artificially synthesized HAP materials can't reach the solubility of biological apatites and realize the continuous bone regeneration with constant dissolution-crystallisation cycles resulted from the smaller size below 50nm of biological apatite crystals, which will influence the repaired results. Nanoscaled HAP has specific physical or chemical properties differing substantially from those bulk HAP materials, which is hopeful to provide feasible means to resolve the above problems. Now there are many methods for the preparing of nanoscaled HAP. Nevertheless, it is required to study the preparation methodology of stable HAP nanoparticles system and HAP nanostructure further. In addition, the unique nano characteristics of nanoscaled HAP should also be deeply analyzed. Therefore, the main content of this paper is to study the preparation technology and nano characteristics of nanoscaled HAP.The study of preparation technology of nanoscaled HAP included two aspects. Firstly, ultrasound assisting and GAGs controlling precipitation method was provided for the preparation of stable HAP nanoparticles. The effects of two important impact factors of GAGs concentration and ultrasound time on the formation and properties of HAP nanoparticles were researched, and the mechanism of this method was also discussed. Secondly, BSA precursor thermolysis method was also provided to fabricate nanoscaled HAP rod-like crystals and bundle-like nanostructure. The impact factors such as BSA concentration and thermal treatment procedure were studied, and the mechanism of this method was also discussed.The study of nano characteristics of nanoscaled HAP was carried out in two aspects. One was the adsorption to biomacromolecule, the other was the interaction with red blood cells (RBCs). Firstly, the adsorbing characteristics of HAP nanoparticles to heparin and BSA were studied by the adsorption isotherms and adsorption rate of heparin and BSA on different size HAP particles. Secondly, four kinds HAP particles such as HAP nanoparticles, non-nano HAP particles, heparin modified nanoparticles and BSA modified nanoparticles were selected to interact with RBCs. The effects of HAP nanoparticles on the aggregation and membrane morphology change of RBCs were studied at micrometer scale and nanometer scale respectively in order to analyze the nano characteristics of nanoparticles to RBCs. Combined with the aggregation models of RBCs, the nano characteristics of HAP nanoparticles inducing the change of RBCs was discussed by the research of interaction between HAP nanoparticles and sialic acid on the membrane surface of RBCs. This can provide some experimental references for the evaluation of blood compatibility of nanomaterials.