La³⁺ and F^- dual-doped multifunctional hydroxyapatite nanoparticles: Synthesis and characterization

Hydroxyapatite (HA) co-doped with La³⁺ and F^- ions were synthesized by the precipitation method and sintered at 1,100°C for 1 hr. Samples were characterized by the standard experimental methods including the density, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) to investigate their microstructure, phase formation, and bonding characteristics in detail. Moreover, the materials produced were identified using the microhardness tests. It was observed that in the most of materials, the hydroxyapatite was found to be the main phase with a minor amount of β-tricalcium phosphate (β-TCP). Furthermore, the presence of fluoride and small amount of β-TCP was verified with all the characteristic FTIR bands of hydroxyapatite for the majority of samples studied. The result in SEM evaluation is that the produced HA powders have less deformed, uniformly distributed, and regularly shaped particles. Here, the material density has changed towards a less dense state with the increasing rate of La doping, but statistically significant difference was not obtained (p, .1942 > .05) with increase of the F doping. A significant difference was obtained the microhardness values between La³⁺ and F^- ions co-doped HA materials and pure HA (p [.0053] < .05). Accordingly, this study confirmed that since the La³⁺ and F^- ions can potentially increase the efficacy of HA. According to the spectral, mechanical, and microstructure analysis result, this material can be as a good candidate product for use as an occluding material for dental application.