Synthesis Of Highly Dispersed Nano-Hydroxyapatite Powder

As the main inorganic component of the animal bone, hydroxyapatite (HA) has good bioactivity and biocompatibility. It is nonpoisonous and safe to transplant into the living body of human being, and it can make a chemical bonding with bone. Therefore, it was mainly used to replace or repair human hard tissues, and it can also be used as drug carrier to control the release and delivery of the drugs. Nano-HA has lots of excellence as drug carrier, and mesoporous materials have many advantages to be drug carrier. So it will have more widely use if mesoporous nano-HA can be synthesized. In our experiments, we aimed at preparing mesoporous structured nano-HA and studying its formation mechanism.First, we choose microbial cells as the template. The chemical precipitation method showed some advantage in many aspects such as the simple synthesis process, low cost potential for mass production and efficiency. At room temperature, using Ca(OH)2 as Ca precursor, mesoporous HA have been synthesized via precipitation method using microbial PJJM cells as a template. It was discussed that the influences of technological conditions such as the concentration of Ca and P precursor, template, and aging time on the morphology, structure and composition of the final product. The optimic technological condition for preparation of mesoporous HA was determined in our experiments.The obtained mesoporous HA were characteristic by many testing methods such as XRD, FTIR, UV-Vis, BM, TEM, FESEM, HRTEM, AFM, EDS, NADI and BJH. The results indicated that the particles are an irregular structure with the diameter of hundreds of nanometer; the mesoporous HA have a weak crystallinity; the Ca/P value was approximately 1.684; the special surface area was 85.96m2/g; the BET average pore volume was 0.2260m3/g; the pore size distribution is in the range of 2.0~40nm which were the pore between the particles to be formed by the loose pileup of particles.The performance was affected by structure; the application was determined by performance. We only make a certain study on fluorescence, wettability, Zeta potential and conductivity to the specimen, and the results showed that it has weak hydrophilicity and some fluorescence. Because of time, the study of drug release property will be delayed.Second, we choose microbial PJJM cells as the template again. At room temperature, using Ca(NO3)2 as Ca precursor, nano-HA have been synthesized via precipitation method using PJJM cells as a template. The results indicated that the bamboo leaf-shaped specimen has the width of 10 nm and 40 nm in length changed into irregular spherical particles with the diameter of 40nm after calcined at 700oC.Finally, we choose polyvinyl alcohol (PVA) as the template. Highly dispersed nano-HA particles have been prepared via a precipitation method. Using Ca(OH)2 as Ca precursor, the size of nano-HA particles is approximately 30nm after calcined at 700oC. using Ca(NO3)2 as Ca precursor, the size of nano-HA particles is approximately 20~30nm after calcined at 700oC. All of them have clear grain boundaries and uniform distribution.