Dissolution at the Nanoscale: Self‐Preservation of Biominerals

Tang, Ruikang; Wang, Lijun; Orme, Christine A.; Bonstein, Tammy; Bush, Peter J.; Nancollas, G.H.

doi:10.1002/ange.200353652

Cited by 50 publications

(69 citation statements)

References 25 publications

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“…It is well-known that the dissolution of calcium phosphate crystals is highly dependent on the degree of saturation, S. Previously, it was considered that when S < 1, and with a constant value of S maintained, all crystals would inexorably dissolve, until the solid phases had disappeared. However, recent CC studies have shown that the rates decrease markedly with time, despite sustained undersaturations (Tang et al, 2004). Microradiography combined with densitometric analysis showed that the surface layer and the interior part of natural caries lesions possessed a high degree of resistance to acid attack, relative to the underlying normal enamel (Aoba and Yagi, 1982).…”

Section: Discussionmentioning

confidence: 99%

Enamel Demineralization in Primary and Permanent Teeth

et al. 2006

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Although enamel demineralization is important for our understanding of caries formation, no consensus has been reached regarding the possible differences in susceptibility of primary and permanent enamel. We used the constant composition (CC) technique to investigate the acid-induced demineralization of these tissues at a relative undersaturation with respect to hydroxyapatite (HAP) of 0.902, pH = 4.5, and ionic strength = 0.15 mol L −1 . The demineralization rates showed significant differences, primary enamel having the greater susceptibility to dissolution during an initial linear stage: 1.5 ± 0.5 × 10 −10 mol mm −2 min −1 compared with 2.6 ± 0.5 × 10 −11 mol mm −2 min −1 for permanent enamel. During the reactions, we observed nanosized crystallites which attached to the enamel surfaces or escaped into the bulk solution. These nanosized crystallites were kinetically protected against further dissolution, even though the solutions remained undersaturated. It is hypothesized that they may contribute to the remarkable mechanical and dynamic characteristics of enamel.

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Section: Discussionmentioning

confidence: 99%

Enamel Demineralization in Primary and Permanent Teeth

et al. 2006

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“…The effects become more important as the particle size approaches the critical length because more of the surface is likely to be composed of steps shorter than the critical length. This new dissolution model incorporating particle size considerations [38,39] can explain bulk demineralization of sparingly soluble salts such as HAP [40][41][42][43][44], which is generally initiated and accompanied by the formation and development of pits on the crystal surfaces; the dissolution rates are also determined by the pit densities and spreading velocities. The rate of step movement from a pit of radius r can be obtained from:…”

Section: Dissolution Model Of Sparingly Soluble Calcium Orthophosphatmentioning

confidence: 99%

Dynamics of crystallization and dissolution of calcium orthophosphates at the near-molecular level

Wang

et al. 2011

Chin. Sci. Bull.

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Although extensive investigations of biogenic and geological calcium phosphate crystallization/dissolution and their phase transformations have been performed, the mechanisms of crystallization and dissolution of sparingly soluble calcium phosphates in geological settings have not been completely determined at the near-molecular level. In particular, an understanding of the physical-chemical processes at the earliest nucleation stage and the subsequent crystal surface dynamics in soil solutions is lacking. This review focuses on the earliest events in homo/heterogeneous nucleation from an initial supersaturated solution phase, the subsequent growth of calcium phosphate phases, and the relevant influences of the presence of additional inorganic and organic molecules in both geological and biological settings. These studies have implications for the understanding of the complex processes of calcium phosphate transformations in soils, and provide possible physical-chemical mechanisms for the biogeochemical behavior of phosphorus at the near-molecular level. calcium orthophosphates, crystallization, dissolution, AFM Citation:Wang L J, Lu J W, Xu F S, et al. Dynamics of crystallization and dissolution of calcium orthophosphates at the near-molecular level.

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“…Tang et al 15 demonstrated that 20-40 nm apatite particles play an important role in biomineral formation. Shi et al 16 reported that sphere-like hydroxyapatite particles with diameters of 20 nm have better effects on promotion of cell growth and inhibition of cell apoptosis than those with diameters of 80 nm.…”

Section: Introductionmentioning

confidence: 99%

Cell responses to two kinds of nanohydroxyapatite with different sizes and crystallinities

Liu

Zhao

et al. 2012

IJN

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Introduction:Hydroxyapatite (HA) is the principal inorganic constituent of human bone. Due to its good biocompatibility and osteoconductivity, all kinds of HA particles were prepared by different methods. Numerous reports demonstrated that the properties of HA affected its biological effects. Methods: Two kinds of nanohydroxyapatite with different sizes and crystallinities were obtained via a hydrothermal treatment method under different temperatures. It was found that at a temperature of 140°C, a rod-like crystal (n-HA1) with a diameter of 23 ± 5 nm, a length of 47 ± 14 nm, and crystallinity of 85% ± 5% was produced, while at a temperature of 80°C, a rod-like crystal (n-HA2) with a diameter of 16 ± 3 nm, a length of 40 ± 10 nm, and crystallinity of 65% ± 3% was produced. The influence of nanohydroxyapatite size and crystallinity on osteoblast viability was studied by MTT, scanning electron microscopy, and flow cytometry. Results: n-HA1 gave a better biological response than n-HA2 in promoting cell growth and inhibiting cell apoptosis, and also exhibited much more active cell morphology. Alkaline phosphatase activity for both n-HA2 and n-HA1 was obviously higher than for the control, and no significant difference was found between n-HA1 and n-HA2. The same trend was observed on Western blotting for expression of type I collagen and osteopontin. In addition, it was found by transmission electron microscopy that large quantities of n-HA2 entered into the cell and damaged the cellular morphology. Release of tumor necrosis factor alpha from n-HA2 was markedly higher than from n-HA1, indicating that n-HA2 might trigger a severe inflammatory response. Conclusion: This work indicates that not all nanohydroxyapatite should be considered a good biomaterial in future clinical applications.

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Dissolution at the Nanoscale: Self‐Preservation of Biominerals

Cited by 50 publications

References 25 publications

Enamel Demineralization in Primary and Permanent Teeth

Enamel Demineralization in Primary and Permanent Teeth

Dynamics of crystallization and dissolution of calcium orthophosphates at the near-molecular level

Cell responses to two kinds of nanohydroxyapatite with different sizes and crystallinities

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