Systematic empirical analysis of calcium–oxygen coordination environment by calcium K-edge XANES

Sowrey, Frank E.; Skipper, Laura J.; Pickup, David M.; Drake, Kieran O.; Lin, Zhongjie; Smith, Mark E.; Newport, Robert J.

doi:10.1039/b311715d

Cited by 91 publications

(80 citation statements)

References 23 publications

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“…19,20 The main edge positions for CaAl-and CaFeLMHs were determined to be quite similar at 4039.9 and 4038.5 eV, respectively. From the previous report by Newport et al, 21 there is a correlation between edge position and coordination number (C.N.) for Ca-containing compounds in the C.N.…”

Section: Resultsmentioning

confidence: 99%

Layered Metal Hydroxides Containing Calcium and Their Structural Analysis

Kim¹,

Heo²,

Paek³

et al. 2012

Bulletin of the Korean Chemical Society

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Layered metal hydroxides (LMHs) containing calcium were synthesized by coprecipitation in solution having two different trivalent metal ions, iron and aluminum. Two mixed metal solutions (Ca 2+ /Al3+ and Ca 2+/Fe 3+ = 2/1) were added to sodium hydroxide solution and the final pH was adjusted to ~11.5 and ~13 for CaAl-and CaFe-LMHs. Powder X-ray diffraction (XRD) for the two LMH samples showed well developed (00l) diffractions indicating 2-dimensional crystal structure of the synthesized LMHs. Rietveld refinement of the Xray diffraction pattern, the local structure analysis through X-ray absorption spectroscopy, and thermal analysis also confirmed that the synthesized precipitates show typical structure of LMHs. The chemical formulae, Ca2.04Al1(OH)6(NO3)·5.25H2O and Ca2.01Fe1(OH)6(NO3)·4.75H2O were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Particle morphology and thermal behavior for the synthesized LMHs were examined by field emission scanning electron microscopy and thermogravimetricdifferential scanning calorimetry.

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Section: Resultsmentioning

confidence: 99%

Layered Metal Hydroxides Containing Calcium and Their Structural Analysis

Kim¹,

Heo²,

Paek³

et al. 2012

Bulletin of the Korean Chemical Society

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“…Untreated B-Cal and N-Cal showed an edge position at 4,037.9 eV, which corresponds to calcite containing six coordinated Ca 2+ . 31 After 48 hours incubation in simulated body fluids, the edge positions of N-Cal shifted to 4,038.8; 4,038.2; and 4,038.6 eV in plasma and in gastric and intestinal fluids, respectively. Similarly, those of B-Cal shifted to 4,038.8; 4,038.6; and 4,038.8, respectively.…”

Section: Physicochemical Parameters Of the Produced Calcium Carbonatesmentioning

confidence: 99%

The fate of calcium carbonate nanoparticles administered by oral route: absorption and their interaction with biological matrices

Lee

Kim

et al. 2015

IJN

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Background Orally administered particles rapidly interact with biological fluids containing proteins, enzymes, electrolytes, and other biomolecules to eventually form particles covered by a corona, and this corona potentially affects particle uptake, fate, absorption, distribution, and elimination in vivo. This study explored relationships between the biological interactions of calcium carbonate particles and their biokinetics. Methods We examined the effects of food grade calcium carbonates of different particle size (nano [N-Cal] and bulk [B-Cal]: specific surface areas of 15.8 and 0.83 m 2 /g, respectively) on biological interactions in in vitro simulated physiological fluids, ex vivo biofluids, and in vivo in gastrointestinal fluid. Moreover, absorption and tissue distribution of calcium carbonates were evaluated following a single dose oral administration to rats. Results N-Cal interacted more with biomatrices than bulk materials in vitro and ex vivo, as evidenced by high fluorescence quenching ratios, but it did not interact more actively with biomatrices in vivo. Analysis of coronas revealed that immunoglobulin, apolipoprotein, thrombin, and fibrinogen, were the major corona proteins, regardless of particle size. A biokinetic study revealed that orally delivered N-Cal was more rapidly absorbed into the blood stream than B-Cal, but no significant differences were observed between the two in terms of absorption efficiencies or tissue distributions. Both calcium carbonates were primarily present as particulate forms in gastrointestinal fluids but enter the circulatory system in dissolved Ca 2+ , although both types showed partial phase transformation to dicalcium phosphate dihydrate. Relatively low dissolution (about 4%), no remarkable protein–particle interaction, and the major particulate fate of calcium carbonate in vivo gastrointestinal fluids can explain its low oral absorption (about 4%) regardless of particle size. Conclusion We conclude that calcium carbonate nanoparticles can act more actively with biological matrices in vitro and ex vivo, but that in vivo, their biological interactions and biokinetics are not affected by particle size.

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“…Phys., 2010, 12, 1081-1091 This journal is c the Owner Societies 2010 that in the biological samples most of the calcium is in an apatite-like environment. 81,82 However, the XANES spectral features become less defined in the natural apatites (especially HB) because of the progressive loss of ordering of the mineral phase (Fig. 4).…”

Section: H{mentioning

confidence: 99%

Probing the calcium and sodium local environment in bones and teeth using multinuclear solid state NMR and X-ray absorption spectroscopy

Laurencin

Wong

Chrzanowski

et al. 2010

Phys. Chem. Chem. Phys.

110

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International audienceDespite the numerous studies of bone mineral, there are still many questions regarding the exact structure and composition of the mineral phase, and how the mineral crystals become organised with respect to each other and the collagen matrix. Bone mineral is commonly formulated as hydroxyapatite, albeit with numerous substitutions, and has previously been studied by 31P and 1H NMR, which has given considerable insight into the complexity of the mineral structure. However, to date, there has been no report of an NMR investigation of the other major component of bone mineral, calcium, nor of common minority cations like sodium. Here, direct analysis of the local environment of calcium in two biological apatites, equine bone (HB) and bovine tooth (CT), was carried out using both 43Ca solid state NMR and Ca K-edge X-ray absorption spectroscopy, revealing important structural information about the calcium coordination shell. The 43Ca diso in HB and CT is found to correlate with the average Ca–O bond distance measured by Ca K-edge EXAFS, and the 43Ca NMR linewidths show that there is a greater distribution in chemical bonding around calcium in HB and CT, compared to synthetic apatites. In the case of sodium, 23Na MAS NMR, high resolution 3Q-MAS NMR, as well as 23Na{31P} REDOR and 1H{23Na} R3-HMQC correlation experiments give the first direct evidence that some sodium is located inside the apatite phase in HB and CT, but with a greater distribution of environments compared to a synthetic sodium substituted apatite (Na-HA)

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Systematic empirical analysis of calcium–oxygen coordination environment by calcium K-edge XANES

Cited by 91 publications

References 23 publications

Layered Metal Hydroxides Containing Calcium and Their Structural Analysis

Layered Metal Hydroxides Containing Calcium and Their Structural Analysis

The fate of calcium carbonate nanoparticles administered by oral route: absorption and their interaction with biological matrices

Probing the calcium and sodium local environment in bones and teeth using multinuclear solid state NMR and X-ray absorption spectroscopy

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