Influence of the addition of carbonated hydroxyapatite and selenium dioxide on mechanical properties and in vitro bioactivity of borosilicate inert glass

Five nanocomposite samples containing different percentages of carbonated hydroxyapatite (CHA), selenium dioxide (SeO2) and inert glass (IG) have been prepared using high-energy ball milling method with the aim of improving the in vitro bioactivity of these nanocomposites. Fourier transform infrared (FTIR) spectroscopy along with X-ray diffraction (XRD) technique was applied on both nanopowders and the sintered nanocomposites to record the structural changes and examine the resultant sintered phases. Mechanical properties were measured by ultrasonic non-destructive technique. In order to assess the bioactivity of the sintered specimens, they were soaked in simulated body fluid for 14 days and then, they were investigated by FTIR and scanning electron microscopy (SEM). Both FTIR and XRD spectra showed that the glasses encouraged the partial HA decomposition to tricalcium phosphate (TCP) and calcium silicate (CaSiO3) phases. The formation of the latter phase along with the remainder HA contents was responsible for good bioactivity and appropriate mechanical properties of the investigated nanocomposites. The successive addition of selenium dioxide to these nanocomposites led to further improvement of their bioactivity without any recorded changes in the mechanical properties. Based on the abovementioned results, the prepared nanocomposites can be used in various tissue-engineering applications.