| With the development of science and technology, new materials are used widely in all areas of the society. The application of biological material has got unprecedented attentions. As the most representative biomaterials, hydroxyapatite (HAP) has been of great interest in the fields of materials and neoteric biomedicine engineering science derived from the most similar composition and crystal structure with a basic mineral of phosphate ores in bones and teeth of living vertebrates. HAP has attracted extensive attention in the field of bone tissue engineering as implants or coatings on prostheses owing to its excellent bioactivity, biocompatibility, osteoconductivity, chemical and physical stability. 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 low dense, low strength and poor mechanism compared with natural bone. In order to solve these problems, many investigations have been carried on such as coating materials, composite materials, and nanomaterials. Some research revealed that properties of HAP are largely dependent on their microstructural features, such as particles size, degree of particles size agglomeration and sintered densities. Compared with pure hydroxyapatite, a biological apatite (like in bone) is non-stoichiometric and contains several different substituents in its structure, mainly carbonate (some percent) and other elements in traces like Mg2+, Na+, Fe2+, Sr2+, Pb2+, HPO42-, F-, Cl-. Therefore, the preparation of fine, single distribution and stable HAP particle is the most important step in achieving a highly sintered ceramic material with desirable microstructure. In this paper, via precipitation method, to synthesize hydroxyapatite nanoparticles (nano-HAP) in a systematic and all-round way, and basically realized the controllability of the sizes and appearances of the as-synthesized nano-HAP. Some mechanism of HAP growth was simply discussed. The main research works were as follows:The high purity and good crystallinity HAP nanorods have been synthesized by precipitation method in aqueous solution. The as-synthesized HAP nanorods had a diameter of 30 nm, and a length of 100 nm, the slightly sharp of both end, which is similar to the HAP inner the human badly. In order to reduce the aggregation of this nano-HAP, we situ-synthesize needle-like HAP, using PAA as food and medical. And the as-prepared nano-HAP could form stable, dispersal nano-HAP suspension, with a well dispersion effects. The effects of the amount of PAA and ultrasonic time on the dispersion stability of nano-scaled HAP were studied by the images absorbance. The dispersion mechanism was preliminarily discussed as well. The experimental results showed that PAA greatly increased the absolute value, which indicated PAA could effectively improve the dispersion stability of the nano-scaled HAP powder in water. The enhancement mechanism of PAA might be resulted from the electrostatic stabilization and steric stabilization. The organic substrate shields the solid surface through PAACa, which decreasing dramatically its surface energy and hence facilitate the dispersion of the filler in a water. So the bad dispersion problem of nano-HAP has effectively been solved, which can widely apply in biological medicine.Firstly using Polyvinylpyrrolidone (PVP) as a template, adopting chemical precipitation method, situ-synthesis nano-HAP with Ca(OH)2 as calcium resource. The product has one-dimensional rodlike structure, with the length of 45 - 130 nm and the diameter of 20 nm, which indicated that PVP have double effect on the dimension and dispersion. To analysis the FESEM photo, we found that PVP can reduce the aggregation of the product, and exhibits extraordinaire dispersion property. Furthermore, larger in the concentration of PVP is, the better the dispersive properties is., the best concentration of PVP is 2.5 g/L. It is also interestingly to find that the nanoparticles could realize membrane penetrating transport in biological research, which is very helpful in the developing of the application of nano-HAP. But the mechanism of the membrane penetrating transport of nano-HAP is unknown, we hope that this is helpful to the biological medicine research.We found that, could control the formation of hydroxyapatite nanorods by a one-step precipitation, which have properties of simple process and low cost. Using self-prepared nano-CaCO3 as calcium source, the reedle-like nano-HAP was fist synthesized by self-assembly method, without any organic matter or inorganic ions, which overcome the disadvantage of long reaction time and complicated operation. Not only the CaCO3 is reactants, but also template, this is the reason why nanoparticle could self-assembled sphere, further there is no impurity phases in the product. The carbonated hydroxyapatite sphere could be applied in the field of bone tissue engineering.The (SiHAP) nanoparticles and porous flower-like hydroxyapatite were first synthesized by precipitation method, using CaCO3 as reactant, and then adding inorganic sodium silicate and aluminum hydroxide, respectively. In the reaction of adding sodium silicate, concentration and pH were investigated. Compared to other synthesis method of silicon-substituted hydroxyapatite, not only the method is simple, but also the operation is convenient, which could provide convenience to the application on industry. In the system of adding aluminum hydroxide, because there is not any additive organic or polymer, avoid the processes of removing template. In this research, the adding of inorganic could promote the conversion rate from CaCO3 to HAP, which provides a new method to reduce the reaction time successfully, also there is no phosphate phase in the XRD pattern. Moreover it is shown that these products are good thermo-stability, after calcined 6 h at 800 oC, there is no phosphate phase in the XRD pattern, shown there no difference in the structure, which have a better prospect of application on chromatographic separation and absorption.Take hollow spherical calcite and phosphate solution as reactants, we successfully synthesis the hollow spherical hydroxyapatite under atmospheric pressure, 60 oC, reacting for 2 h, and also discuss the mechanism of the reaction. CaCO3 is not only reactant, but also template, without any organic matter or inorganic ions, single hydroxyapatite is synthesized, without any other calcium phosphate salt intermediate. The reaction temperature and time could effectively influence the preparation of hollow sphere, the best reaction condition is 60 oC, 2 h. Moreover the temperature is too high or too low, the structure of hollow sphere can not be formatted.In this thesis, we attempted a biomimetic method to obtained nano-HAP with special properties, introduced a novel ideal to synthesis nano- HAP. In-situ technique employed during preparation process, which introduced functional groups upon the surface of nano-HAP overcoming the agglomeration of nanoparticles. For the benefits of simple, uninterrupted and inexpensive, this innovatory technique has potential use in application and guide meaning in large-scale industrialization manufacture of nano-HAP.
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