Synthesis and characterization of pure and strontium doped hydroxyapatite by sono-chemical assisted hydrothermal technique

Abstract

Hydroxyapatite (HA) is the most stable Calcium Phosphate salt (also known as Bone-mineral) which is present as inorganic part of human hard tissues having applications in orthopedics, dentistry, archeology, chromatography, environmental remedies as waste water treatment, pollutant gas adsorbent and so on. In this study an attempt is made to synthesize pure Hydroxyapatite and 5 wt% Strontium doped Hydroxyapatite (Sr doped HA) NPs using sono-chemical assisted hydrothermal technique. Strontium (Sr) is an essential trace mineral present in bone and it improves biological properties of HA so Sr is selected as dopant. Synthesized samples were characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) spectroscopy and Energy Dispersive X-Ray (EDX) Analysis. XRD analysis shows that XRD data of both samples match well with standard data (JCPDS Card No.- 09-0432) and have hexagonal crystal symmetry. Sr substitution in HA lattice increase cell parameters and shift diffraction peaks slightly to the lower value of diffraction angles. FT-IR analysis shows that all the characteristic transmission bands of Phosphate and hydroxide groups along with peaks of adsorbed water are present in FT-IR spectra of pure and Sr doped HA. However, transmission peaks of Nitrate are also present due to the fact that Nitrate compound was utilized in the reaction as calcium source. EDX analysis shows the presence of Sr ion in HA lattice. Ca/P ratio was 1.98 and 1.88 for pure HA and Sr doped HA respectively. High Ca/P ratio might be found due to presence of small amount of amorphous intermediate Calcium Phosphate phases or due to formation of Tetra-calcium Phosphate.