The Role and Implications of Bassanite as a Stable Precursor Phase to Gypsum Precipitation

Driessche, Alexander E. S. Van; Benning, Liane G.; Rodríguez-Blanco, Juan Diego; Ossorio, M.; Bots, Pieter; García‐Ruiz, Juan Manuel

doi:10.1126/science.1215648

Cited by 300 publications

(346 citation statements)

References 32 publications

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“…16 As these particles are not isolated from the solution, the stabilization of these metastable polymorphs cannot be attributed to the absence of water. Instead, we proposed that the aggregation-based transformation of the metastable polymorph hemihydrate to gypsum 53,54 would be affected by the restricted volume. 16 The diffusive transport of particles is severely hindered when the surface separation approaches the particle diameter such that aggregation would be slower or not occur to the same extent in confinement.…”

Section: Discussionmentioning

confidence: 99%

Confinement Increases the Lifetimes of Hydroxyapatite Precursors

2014

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The mineral component of bone is a carbonated, non-stoichiometric hydroxyapatite (calcium phosphate) that forms in nanometer confinement within collagen fibrils, the principal organic constituent of bone. We here employ a model system to study the effect of confinement on hydroxyapatite precipitation from solution under physiological conditions. In common with earlier studies of calcium carbonate and calcium sulfate precipitation, we find that confinement significantly prolongs the lifetime of metastable phases, here amorphous calcium phosphate (ACP) and octacalcium phosphate (OCP). The effect occurs at surprisingly large separations of up to 1 m, and at 0.2 m the lifetime of ACP is extended by at least an order of magnitude. The soluble additive poly(aspartic acid), which in bulk stabilizes ACP, appears to act synergistically with confinement to give a greatly enhanced stability of ACP. The reason for the extended lifetime appears to be different from that found with CaCO 3 and CaSO 4 , and underscores both the variety of mechanisms whereby 2 confinement affects the growth and transformation of solid phases, and the necessity to study a wide range of crystalline systems to build a full understanding of confinement effects. We suggest that in the case of ACP and OCP the extended lifetime of these metastable phases is chiefly due to a slower transport of ions between a dissolving metastable phase, and the more stable, growing phase. These results highlight the potential importance of confinement on biomineralisation processes.3

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Section: Discussionmentioning

confidence: 99%

Confinement Increases the Lifetimes of Hydroxyapatite Precursors

2014

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“…But, new experimental evidence has revealed that gypsum precipitation does not proceed via a direct nucleation pathway. Instead, a variety of multi-step pathways have been proposed including amorphous calcium sulphate and bassanite as possible precursor phases [7][8][9][10]. However, all these studies are mainly based on ex situ characterization of the precipitation reaction (e.g., electron microscopic imaging combined with quenching techniques to isolate the precipitates from solution for their subsequent characterization).…”

Section: Introductionmentioning

confidence: 99%

Physicochemical and Additive Controls on the Multistep Precipitation Pathway of Gypsum

et al. 2017

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Synchrotron-based small-and wide-angle X-ray scattering (SAXS/WAXS) was used to examine in situ the precipitation of gypsum (CaSO 4 ·2H 2 O) from solution. We determined the role of (I) supersaturation, (II) temperature and (III) additives (Mg 2+ and citric acid) on the precipitation mechanism and rate of gypsum. Detailed analysis of the SAXS data showed that for all tested supersaturations and temperatures the same nucleation pathway was maintained, i.e., formation of primary particles that aggregate and transform/re-organize into gypsum. In the presence of Mg 2+ more primary particle are formed compared to the pure experiment, but the onset of their transformation/reorganization was slowed down. Citrate reduces the formation of primary particles resulting in a longer induction time of gypsum formation. Based on the WAXS data we determined that the precipitation rate of gypsum increased 5-fold from 4 to 40 • C, which results in an effective activation energy of~30 kJ·mol −1 . Mg 2+ reduces the precipitation rate of gypsum by more than half, most likely by blocking the attachment sites of the growth units, while citric acid only weakly hampers the growth of gypsum by lowering the effective supersaturation. In short, our results show that the nucleation mechanism is independent of the solution conditions and that Mg 2+ and citric acid influence differently the nucleation pathway and growth kinetics of gypsum. These insights are key for further improving our ability to control the crystallization process of calcium sulphate.

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“…The two likely candidates are the aqueous phase in the parasite digestive vacuole (DV) 17,18 and the lipid subphase that has been reported to reside either in the DV bulk 19,20 or along the DV membrane 17,21 . The mechanism of hematin crystallization may be classical, i.e., addition of molecules to growth sites 22 , or nonclassical, i.e., association of precursors [23][24][25] . The mechanism of action of the inhibitor species, it is possible that the inhibitors either reduce the concentration and activity of hematin in the growth medium through complexation 26,27 , or interfere with crystallization by binding to the crystal surface(s) and restricting solute addition.…”

Section: Introductionmentioning

confidence: 99%

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2017

IJPSR

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ABSTRACT:One of the factors responsible for malaria pathogenesis is the suppression of host immune responses. This suppression enhances parasitemia and diminishes the host immune response to malaria-expressed proteins and other pathogens. Hemozoin is a key metabolite associated with severe malaria anemia (SMA), immunosuppression, and cytokine dysfunction. Targeting of this pigment may be necessary in the design of new therapeutic products against malaria. In the present research, some novel compounds are synthesized and targeted against hemozoin growth. The consideration of new chemotherapeutic targets in malaria research is most likely to identify new classes of drugs. The present work deals with the synthesis of a small library of 2-alkoxy/phenoxy-3-amino-3-arylpropan-1-ols by reductive ring opening of the corresponding azetidine-2-ones. After characterization of synthesized compounds, these were evaluated for hemozoin formation inhibition assay. The results showed that all compounds are inhibiting hemozoin formation comparable to Clotrimazole. This may be concluded that the synthesized compounds exhibit antimalarial activity via inhibition of hemozoin formation.

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The Role and Implications of Bassanite as a Stable Precursor Phase to Gypsum Precipitation

Cited by 300 publications

References 32 publications

Confinement Increases the Lifetimes of Hydroxyapatite Precursors

Confinement Increases the Lifetimes of Hydroxyapatite Precursors

Physicochemical and Additive Controls on the Multistep Precipitation Pathway of Gypsum

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