Simultaneous structural and surface modifications of nanophase hydroxyapatite for improving its dissolution and bioactivity

The aim of this study was to improve the dissolution rate and bioactivity of nanophase hydroxyapatite (HA). For this purpose, simultaneous structural and surface modifications of nanophase HA was made by incorporating SiO44- into the HA structure and creating a silica layer on its surface via the sol-gel method. Characterization of the prepared nanopowders was performed by transmission electron microscopy, X-ray diffractometer, Fourier transformed infrared spectroscopy, and acid dissolution testing. An atomic absorption spectrometer was used to determine calcium ions concentration in physiological saline solution. Results revealed that the simultaneous structural and surface modifications of nanophase HA had a considerable increasing effect on calcium ion release from nanophase HA, and on surface reprecipitation rate of calcium ions, respectively. The obtained results suggest that this modified nanophase HA could be used as a new bioceramic for bone repair.