Revisiting the localization of Zn2+ cations sorbed on pathological apatite calcifications made through X-ray absorption spectroscopy

Journal Article · Wed Apr 01 04:00:00 EDT 2009 · Biochimie

DOI:https://doi.org/10.1016/j.biochi.2009.05.009· OSTI ID:980775

Bazin, D; Carpentier, X; Brocheriou, I; Dorfmuller, P; Aubert, S; Chappard, C; Thiaudiere, D; Reguer, S; Waychunas, G; Jungers, P; Daudon, M

The role of oligo-elements such as Zn in the genesis of pathological calcifications is widely debated in the literature. An essential element of discussion is given by their localization either at the surface or within the Ca apatite crystalline network. To determine the localization, X-ray absorption experiments have been performed at SOLEIL. The Exafs results suggest that Zn atoms, present in the Zn{sup 2+} form, are bound to about 4 O atoms at a distance of 2.00{angstrom}, while the interatomic distance R{sub CaO} ranges between 2.35 {angstrom} and 2.71 {angstrom}. Taking into account the content of Zn (around 1000 ppm) and the difference in ionic radius between Zn{sup 2+} (0.074 nm) and Ca{sup 2+} (0.099 nm), a significant longer interatomic distance would be expected in the case of Zn replacing Ca within the apatite crystalline network. We thus conclude that Zn atoms are localized at the surface and not in the apatite nanocrystal structure. Such structural result has essential biological implications for at least two reasons. Some oligoelements have a marked effect on the transformation of chemical phases, and may modify the morphology of crystals. These are both major issues because, in the case of kidney stones, the medical treatment depends strongly on the precise chemical phase and on the morphology of the biological entities at both macroscopic and mesoscopic scales.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Earth Sciences Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 980775
• Report Number(s): LBNL-2933E
• Journal Information: Biochimie, Journal Name: Biochimie Journal Issue: 10 Vol. 91
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
ABSORPTION
ABSORPTION SPECTROSCOPY
APATITES
ATOMS
INTERATOMIC DISTANCES
KIDNEYS
MORPHOLOGY
ORIGIN
TRANSFORMATIONS