Facile Preparation of Controllable-Aspect-Ratio Hydroxyapatite Nanorods with High-Gravity Technology for Bone Tissue Engineering.

As the main inorganic component of human hard tissue, hydroxyapatite (HAp) has attracted extensive interest in biomedical and clinical applications, especially for HAp nanoparticles. In this study, HAp nanorods with a controllable aspect ratio were successfully prepared using NH3•H2O and CO(NH2)2 as aspect ratio modifier by a high-gravity reactive precipitation in a rotating packed bed (RPB) combined with hydrothermal treatment. The influences of the molar ratio of NH3•H2O and CO(NH2)2 and the rotating speed on the average size and aspect ratio of HAp nanorods were systematically explored. The as-synthesized HAp nanorods were investigated with TEM, XRD, and FTIR. The results indicated that the average aspect ratio of HAp nanorods could be facilely controlled in the range 2.2-39. As compared to a traditional batch stirred tank reactor, the RPB reactor had HAp nanorods with a smaller particle width and a wider range of aspect ratio, and a much shorter reaction time from 20 min to 1 s. Further, the potential use of HAp nanorods in the pectin/HAp nanocomposite cements was investigated. The pectin/HAp nanocomposite cement with the highest compressive strength of 29.7 MPa was achieved with the addition of HAp nanorods with the aspect ratio of 15. [ABSTRACT FROM AUTHOR]