Iron in Hydroxyapatite: Interstitial or Substitution Sites?

Iron-doped hydroxyapatite (Fe-HAp) is regarded as a promising magnetic material with innate biocompatibility. Despite the many studies reported in the literature, a detailed theoretical description of Fe inclusions is still missing. There is even no consensual view on what kind of Fe defects take place in Fe-HAp-iron interstitial or calcium substitutions? In order to address these questions, we employ modern first-principles methodologies, including hybrid density functional theory, to find the geometry, electronic, magnetic and thermodynamic properties of iron impurities in Fe-HAp.

Cu-doping of calcium phosphate bioceramics: From mechanism to the control of cytotoxicity.

Unlabelled: In this study, the Cu-doping mechanism of Biphasic Calcium Phosphate (BCP) was thoroughly investigated, as was its ionic release behavior, in order to elucidate cytotoxicity features of these bioceramics. BCP are composed of hydroxyapatite (Ca(PO)(OH)) and β-TCP (Ca(PO)). The two phases present two different doping mechanisms.

Atomic scale modeling of iron-doped biphasic calcium phosphate bioceramics.

Unlabelled: Biphasic calcium phosphates (BCPs) are bioceramics composed of hydroxyapatite (HAp, Ca(PO)(OH)) and beta-Tricalcium Phosphate (β-TCP, Ca(PO)). Because their chemical and mineral composition closely resembles that of the mineral component of bone, they are potentially interesting candidates for bone repair surgery, and doping can advantageously be used to improve their biological behavior. However, it is important to describe the doping mechanism of BCP thoroughly in order to be able to master its synthesis and then to fully appraise the benefit of the doping process.

X-ray absorption spectroscopy shining (synchrotron) light onto the insertion of Zn in calcium phosphate ceramics and its influence on their behaviour under biological conditions.

The present study gives a fine description of the Zn location in Zn-doped Biphasic Calcium Phosphate (BCP) samples heat treated between 500 °C and 1100 °C. Structural considerations were used to explain the sample interactions with biological fluid (DMEM). X-ray Absorption Spectroscopy (XAS) experiments were used to characterize the powdered samples.

On the effect of temperature on the insertion of zinc into hydroxyapatite.

Rietveld analysis of X-ray powder diffraction patterns recorded from 28 hydroxyapatite (HAp) samples containing various amounts of zinc (0, 1.6, 3.2 and 6.