Synthesis and thermal decomposition of layered calcium phosphates including carboxylate ions

Sakamoto, Kiyoko; Yamaguchi, Shunro; Kaneno, Motoki; Fujihara, Ichiro; Satoh, Katsuhiko; Tsunawaki, Yoshiaki

doi:10.1016/j.tsf.2008.09.050

Cited by 23 publications

(11 citation statements)

References 11 publications

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“…OCP-citrate was synthesized and its identity was confirmed as described in Materials and Methods and SI Materials and Methods. Microanalysis of our OCP-citrate samples gave a carbon content of 3.49 ± 0.16 wt% and energydispersive X-ray spectroscopy gave a Ca/P ratio of 2.01 ± 0.55 (these broad compositional ranges are typical for OCP-di-/ tricarboxylic acid double salts) (20,21,31) and a compositional formula of Ca 16 (PO 4 ) 8 (HPO 4 ) 3 (HCIT). (11 ± 1)H 2 O; all are in agreement with the stoichiometric approximation to the structural equation (20,31), with one citrate anion per unit cell.…”

Section: Resultsmentioning

confidence: 94%

“…Subsequently, these double salt compounds were shown to have crystallographic structures similar to the parent OCP structure (Fig. 1) by powder X-ray diffraction (XRD) (20,21); in all cases, the unit cell of the double salt was shown to be expanded along the a axis, whereas the b and c unit cell dimensions remained largely unchanged, leading to the proposal that the organic acid anions were incorporated into the (100) plane/hydrated layer. According to the compositional formula, the organic acid anion replaces one of the hydrogen phosphate sites in the OCP structure [i.e., one of the P5 or P6 sites in the OCP structure (22) shown in Fig.…”

Section: Significancementioning

confidence: 99%

See 1 more Smart Citation

Citrate bridges between mineral platelets in bone

Davies

Müller

Wong

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

256

246

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We provide evidence that citrate anions bridge between mineral platelets in bone and hypothesize that their presence acts to maintain separate platelets with disordered regions between them rather than gradual transformations into larger, more ordered blocks of mineral. To assess this hypothesis, we take as a model for a citrate bridging between layers of calcium phosphate mineral a double salt octacalcium phosphate citrate (OCPcitrate). We use a combination of multinuclear solid-state NMR spectroscopy, powder X-ray diffraction, and first principles electronic structure calculations to propose a quantitative structure for this material, in which citrate anions reside in a hydrated layer, bridging between apatitic layers. To assess the relevance of such a structure in native bone mineral, we present for the first time, to our knowledge, 17 O NMR data on bone and compare them with 17 O NMR data for OCP-citrate and other calcium phosphate minerals relevant to bone. The proposed structural model that we deduce from this work for bone mineral is a layered structure with thin apatitic platelets sandwiched between OCP-citrate-like hydrated layers. Such a structure can explain a number of known structural features of bone mineral: the thin, plate-like morphology of mature bone mineral crystals, the presence of significant quantities of strongly bound water molecules, and the relatively high concentration of hydrogen phosphate as well as the maintenance of a disordered region between mineral platelets.NMR crystallography | biomineralization B one is a complex organic-inorganic composite material (1), in which calcium phosphate nanoparticles are held within a primarily collagen protein matrix. The mineral component is a poorly crystalline phase, closely related to hydroxyapatite. The currently accepted model of bone mineral is ∼50-to 150-nmthick stacks of very closely packed apatitic platelets, each of order 2.5-4 nm in thickness (1-4), arranged so that their large (100) faces are parallel to each other and their c axes are strongly ordered (parallel to collagen fibrils) (5). NMR studies show that, in addition to the largely ordered but nonstoichiometric apatitic phase, there is a substantial, highly hydrated, disordered phase containing up to 55% of the bone mineral phosphatic ions (6, 7) but in the form of hydrogen phosphate or phosphate strongly hydrogen-bonded to water rather than apatitic orthophosphate (8). This phase has been assigned as a surface phase, but whether the surface in question is that of individual mineral platelets or the surface of the overall structure formed by a stack of such platelets is not yet clear. There is, however, significant experimental evidence that is not explained by this model as it stands. First, there has never been any observation of an isolated mineral platelet in mature bone, even in preparations in which there have been attempts to disperse the mineral structures (9). This feature suggests that the mineral platelets are not independent structures-indeed, their ordered aggregati...

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Section: Resultsmentioning

confidence: 94%

Section: Significancementioning

confidence: 99%

Citrate bridges between mineral platelets in bone

Davies

Müller

Wong

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

256

246

View full text Add to dashboard Cite

show abstract

“…We have followed a methodology similar to that used in our recent study of interactions between Al(III) and Cr(III) and carboxylate-based surfactants. 45 Calcium ions are of strong interest due to their industrial, environmental and biological importance, and the carboxylates of these ions play an important role in a number of different areas, such as biomaterials, [46][47][48] food industry, 49 paper recycling industry 50,51 and detergency. 52,53 The precipitates formed from precipitation of calcium or magnesium salts of long chain carboxylic acids are the well-known ''soap scums'' formed around washbasins and bathtubs in areas with hard water, 54 and the development of good formulations to avoid these is of considerable importance.…”

Section: Introductionmentioning

confidence: 99%

What drives the precipitation of long-chain calcium carboxylates (soaps) in aqueous solution?

Pereira

Valente

Fernandes

2012

Phys. Chem. Chem. Phys.

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The interaction of sodium octanoate, decanoate or dodecanoate with calcium(ii) in aqueous solutions has been studied using turbidity, conductivity and potentiometric measurements. These show a marked alkyl chain length dependence on the behaviour. At the calcium concentration used (1.0 mM), there is little interaction with the octanoate, the decanoate shows initially formation of a 1:1 complex, followed by precipitation, while the dodecanoate precipitates at low surfactant concentrations. The solid calcium carboxylates were prepared, and show lamellar, bilayer structures with planes of calcium(II) ions coordinated to carboxylate groups through bidentate chelate linkages. Thermogravimetry and elemental analyses indicate the presence of coordinated water with the calcium decanoate but not with longer chain carboxylates. The results of both the solution and solid state studies suggest that precipitation of long-chain carboxylates depends on a balance between hydration effects and hydrophobic (largely van der Waals') interactions. Electrostatic effects make little energetic contribution but play the important structural role of ordering the carboxylate anions before precipitation. Differences are observed in the interactions between calcium(II) and long chain alkylcarboxylates and alkylsulfates, and are interpreted in terms of stronger binding to the metal of the carboxylate group. A general mechanism is proposed for calcium carboxylate precipitation from aqueous solution based on this and previous studies.

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“…The Xray diffraction (XRD) analysis of calcium phosphate powders collected from different levels of the tube with LRs has shown that HA deposits at the beginning of the experiment (Figure 5a, curve 2), while at the bottom of the tube (the end of the experiment) there is a phase of calcium hydrogen phosphate hydrate. [27,28] Different phases could be obtained due to the Ca 2þ gradient occurred during the diffusion of the certain volume of CaCl 2 through the agar gel. It is known that HA forms at the Ca/P ratio of 1.67.…”

Section: Resultsmentioning

confidence: 99%

Self‐Assembled Liesegang Rings of Hydroxyapatite for Cell Culturing

Eltantawy

Belokon

Belogub³

et al. 2021

Advanced NanoBiomed Research

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A novel method of 3D self‐organization of patterns made of biomimetic hydroxyapatite (HA) in agar matrix is reported. The model system involves gradual ion diffusion and phase transitions of calcium phosphates. Herein, HA is precipitated for the first time in the agar gel matrix via single‐diffusion gel growth technique to aggregate the inorganic Liesegang rings (LRs). These patterns are formed as periodic structures through precipitation reaction and arise during the reagent diffusion in a polymer matrix. The concentrations of these inner and outer electrolytes, as well as pH and temperature effects on the morphologies, periodicity, stability, and number of LRs, are studied. In this study, the periodic HA Liesegang ring structures (HA LRs) are fabricated via a diffusion‐limited aggregation process. These patterns influence the C2C12 cell growth and allow to obtain the patterns formed by the cell tissue. This method can be prospective for the generation of 3D gradients in materials/3D gradient materials generation for studying the interface tissue engineering, systematic cell–biomaterial interaction, as well as for the fabrication of the stimuli‐responsive gradients to control/mimic migration of cells during the wound healing.

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Synthesis and thermal decomposition of layered calcium phosphates including carboxylate ions

Cited by 23 publications

References 11 publications

Citrate bridges between mineral platelets in bone

Citrate bridges between mineral platelets in bone

What drives the precipitation of long-chain calcium carboxylates (soaps) in aqueous solution?

Self‐Assembled Liesegang Rings of Hydroxyapatite for Cell Culturing

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