Calculation of 29Si NMR shifts of silicate complexes with carbohydrates, amino acids, and muhicarboxylic acids: potential role in biological silica utilization

Sahai, Nita

doi:10.1016/s0016-7037(03)00425-3

Cited by 22 publications

(14 citation statements)

References 65 publications

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“…1). Sahai and Tossell, 2001;Sahai, 2004). The increased soluble Si concentration, however, did not affect the cells, which indicates that Si was nontoxic at these concentrations.…”

Section: Mineral Toxicity Mechanismsmentioning

confidence: 89%

Did Mineral Surface Chemistry and Toxicity Contribute to Evolution of Microbial Extracellular Polymeric Substances?

Campbell

Zhang

et al. 2012

Astrobiology

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Modern ecological niches are teeming with an astonishing diversity of microbial life in biofilms closely associated with mineral surfaces, which highlights the remarkable success of microorganisms in conquering the challenges and capitalizing on the benefits presented by the mineral-water interface. Biofilm formation capability likely evolved on early Earth because biofilms provide crucial cell survival functions. The potential toxicity of mineral surfaces toward cells and the complexities of the mineral-water-cell interface in determining the toxicity mechanisms, however, have not been fully appreciated. Here, we report a previously unrecognized role for extracellular polymeric substances (EPS), which form biofilms in shielding cells against the toxicity of mineral surfaces. Using colony plating and LIVE/DEAD staining methods in oxide suspensions versus oxide-free controls, we found greater viability of wild-type, EPS-producing strains of Pseudomonas aeruginosa PAO1 compared to their isogenic knockout mutant with defective biofilm-producing capacity. Oxide toxicity was specific to its surface charge and particle size. High resolution transmission electron microscopy (HRTEM) images and assays for highly reactive oxygen species (hROS) on mineral surfaces suggested that EPS shield via both physical and chemical mechanisms. Intriguingly, qualitative as well as quantitative measures of EPS production showed that toxic minerals induced EPS production in bacteria. By determining the specific toxicity mechanisms, we provide insight into the potential impact of mineral surfaces in promoting increased complexity of cell surfaces, including EPS and biofilm formation, on early Earth.

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“…1). Sahai and Tossell, 2001;Sahai, 2004). The increased soluble Si concentration, however, did not affect the cells, which indicates that Si was nontoxic at these concentrations.…”

Section: Mineral Toxicity Mechanismsmentioning

confidence: 89%

Did Mineral Surface Chemistry and Toxicity Contribute to Evolution of Microbial Extracellular Polymeric Substances?

Campbell

Zhang

et al. 2012

Astrobiology

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“…the processes whereby diatoms extract silicic acid [Si(OH) 4 ] at parts-per-million from water and concentrate it millions of times to create reservoirs of 0.3-0.5 M soluble silica used in creating intricately structured silica shells, lends credence to this idea. [37][38][39][40][41][42][43][44] The likelihood of OSAs or other Q x species forming during the biosilicification process seems to be supported by the following observations. The choline structure is very similar to hydroxyamino acids found in sponge filament proteins.…”

Section: ð1þmentioning

confidence: 95%

Nanobuilding blocks based on the [OSiO1.5]x (x= 6, 8, 10) octasilsesquioxanes

2005

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The dissolution of high surface area silica with tetralkylammonium hydroxides at concentrations greater than 0.2 M, produces polyanionic cage structures, [R 4 N + ][ 2 OSiO 1.5 ] x or Q x , where x 5 6, 8 or 10. The value x depends on the type of alkyl or alkanol group. If R 5 Me or Me 3 NCH 2 CH 2 OH + group (choline) x 5 8 is favored. These silicate anions can be functionalized by reaction with chlorosilanes or siloxanes to produce [RSiMe 2 OSiO 1.5 ] x . The octafunctional molecules are 1.2-1.4 nm in diameter, each functional group occupies a different octant in Cartesian space and as such all functional groups are either orthogonal to or opposite each other. This highly symmetrical structure offers the opportunity to construct multiple kinds of materials one nanometer at a time in one, two or three dimensions. In this review, we discuss methods of synthesizing the polyanionic silicates, their transformation into octafunctional building blocks, ''cubes,'' and their use in formulating polyfunctional compounds and nanocomposites therefrom. Examples of tailoring global properties by tailoring the chemistries used to link cubes are given.

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“…Cerruti et al [39,43] pioneered this approach on sol-gel bioactive glasses, and studied their surface reactivity with probe molecule-based spectroscopic and calorimetric techniques typically used to study catalysts. Experimental work in this field is paralleled by multi-scale computational models, which can provide an atomistic description of the average phenomena measured experimentally [5,8,37,38,41,[44][45][46][47]. Even though not specific on surfaces, excellent reviews of computational models of the structure and reactivity of bioactive glasses have been published recently [48,49].…”

Section: (B) Characterization Toolsmentioning

confidence: 99%

Surface characterization of silicate bioceramics

Cerruti

2012

Phil. Trans. R. Soc. A.

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The success of an implanted prosthetic material is determined by the early events occurring at the interface between the material and the body. These events depend on many surface properties, with the main ones including the surface's composition, porosity, roughness, topography, charge, functional groups and exposed area. This review will portray how our understanding of the surface reactivity of silicate bioceramics has emerged and evolved in the past four decades, owing to the adoption of many complementary surface characterization tools. The review is organized in sections dedicated to a specific surface property, each describing how the property influences the body's response to the material, and the tools that have been adopted to analyse it. The final section introduces the techniques that have yet to be applied extensively to silicate bioceramics, and the information that they could provide.

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Calculation of 29Si NMR shifts of silicate complexes with carbohydrates, amino acids, and muhicarboxylic acids: potential role in biological silica utilization

Cited by 22 publications

References 65 publications

Did Mineral Surface Chemistry and Toxicity Contribute to Evolution of Microbial Extracellular Polymeric Substances?

Did Mineral Surface Chemistry and Toxicity Contribute to Evolution of Microbial Extracellular Polymeric Substances?

Nanobuilding blocks based on the [OSiO1.5]x (x= 6, 8, 10) octasilsesquioxanes

Surface characterization of silicate bioceramics

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