Synthesis and Optimization of Colloidal Hydroxyapatite Nanoparticles by Hydrothermal Processes

This paper reports an optimized, simple, fast and inexpensive method for hydroxyapatite (HA) nanoparticle synthesis. Through a multivariate statistical analysis using a factorial design with 23 resolution, an empirical model was developed which allows control of the shape and size of the HA nanoparticles. This model was used to synthesize HA nanoparticles with sizes between 8 and 600 nm, formed by oriented attachment growth mechanism. The structure was confirmed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images, which also showed that HA nanoparticles had well-defined nanorod forms and narrow size distributions. It was observed that the model is statistically significant and the main parameter for the growth of crystals in the hydrothermal process was temperature.