Investigation of HA Nano-Crystallite Size Crystallographic Characterizations in NHA, BHA and HA Pure Powders and Their influence on Biodegradation of HA

摘要

The mineral or inorganic component of bone is a calcium phosphate idealized as a calcium hydroxyapatite, HA, Ca_(10)(PO_4)_6(OH)_2. Changes in the composition of the apatite affect its lattice parameters, morphology, crystallinity (reflecting crystal size and/or perfection) and finally dissolution properties. In regard to the above points, lattice parameters are expected to have better dissolution properties. Estimation of HA nano crystallite size lattice parameters is one of the most important factors for dissolution properties of bone apatites. In present work, the composition of apatite induce complex structures at the unit-cell level and play a role in influencing the dissolution rate of apatites, which may favour osteointegration. The samples are consist of NHA, bovine bone heated at 850°C for 3 h; BHA, human bone heated at 900°C for 2 h and PHA, HA pure powder. The results estimated by XRD data indicate that increasing in c/a ratio of HA, which is leading to increasing in crystallinity, induce decrease at HA dissolution or improving its chemical solubility in simulated body fluid (SBF). As, it was concluded that the biodegradation of HA decrease in PHA sample.