Structural characterization of zinc-substituted hydroxyapatite prepared by hydrothermal method

Abstract

Zinc-substituted hydroxyapatite (Zn-HA) powders were prepared by hydrothermal method using Ca(NO(3))(2), (NH(4))(3)PO(4) and Zn(NO(3))(2 )as reagents. X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM) were used to characterize the crystalline phase, microstructure, chemical composition, morphology and thermal stability of Zn-HA. The results show that the substitution content of zinc (Zn) in Zn-HA powders prepared in NaOH solution is higher than that prepared in NH(3) solution, and is lower than that of the corresponding amount of starting materials. The substitution of the Zn ion for calcium ion causes a lower crystallinity of Zn-HA and changes the lattice parameters of Zn-HA, since the ionic radius is smaller in Zn(2+) (0.074 nm) than in Ca(2+ )(0.099 nm). Furthermore, the substitution of the Zn ions restrains the growth of Zn-HA crystal and decreases the thermal stability of Zn-HA. Zn-HA powder prepared in NH(3) solution starts to decompose at 800 degrees C when the Zn fraction increases to 15 mol%, while that prepared in NaOH solution start to decompose at 5 mol% Zn. The substitution content of Zn significantly influences the thermal stability, microstructure and morphology of Zn-HA.

Effect of Cu2+ ion on Biological Performance of Nanostructured Fluorapatite Doped with Copper

“…Since the ionic radius of Ca 2+ (0.99 A) is larger than that of Cu 2+ (0.72 A), substitution of Cu 2+ into Ca 2+ position distorts the FA structure. The result shows the decrease of stability of the FA structure and subsequent lowering of the height of the apatite peaks [22].…”

Multifunctional and hybrid systems based on calcium-phosphate and hydroxyapatite for preventive and regenerative medicine

“…Sinteza Zn-HAp se pretežno izvodi metodom precipitacije [35][36][37], jonskom izmenom [38], hidrotermalnom sintezom [39], kao i sol-gel procesima [40]. Jonski radijus Zn 2+ jona iznosi 0,074 nm i manji je u poređenju sa Ca 2+ jonskim radijusom koji iznosi 0,099 nm, pa je i očekivano da se parametri rešetke Zn-HAp promene.…”

Biomimetic Fabrication of Apatite Related Biomaterials

“…It also facilitated the nucleation of HAp, therefore, Sr-containing HAp is might be usable as a template for growing new bone (Pan et al, 2009). Zn-containing HAp increases the specific surface area (Tonegawa et al, 2007) and decreases the thermal stability of HAp (Li et al, 2008). Thus, ionic substitution, which occurs in natural apatite, is effective for controlling both material and biological characteristics of apatite.…”