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Patwardhan, Siddharth V.; Clarson, Stephen J.

doi:10.1023/a:1021243810915

Cited by 91 publications

(79 citation statements)

References 14 publications

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“…Selected area electron diffraction (SAD) of silica hexagons synthesised in a related system, but based on a TMOS silica precursor, revealed an amorphous nature [9,22]. Despite the different reaction kinetics expected for different precursor systems, there was not a significant difference observed in the particle size when the PLL-facilitated silica particles in the TMOS-based and EGMS-based and systems were compared [9,11,20,22].…”

Section: Resultsmentioning

confidence: 99%

Macromolecule mediated bioinspired silica synthesis using a diol-modified silane precursor

et al. 2005

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Silicon isotope geochemistry is a relatively new branch of environmental change research. Here we review the recent developments in the preparation of materials, analytical methods and applications of stable silicon isotope geochemistry in the most common types of biogenic silica currently being analysed. These materials are: diatom, radiolarian and siliceous sponges in lake and ocean sediments and plant phytoliths which are preserved in soils. Despite analyses of Si isotopes being carried out on rocks and minerals since the 1950's and the increasingly widespread use of Si isotopes since the 1990's, to date only a relatively small number of studies have applied Si isotope ratios to environmental change. In lake and ocean sediments the analysis of Si isotope ratios from biogenic materials has the potential to provide an important source of palaeoenvironmental information, especially where carbonates are not preserved. In plants and soils few studies have used Si isotopes, but important advances have recently been made in the understanding within plant fractionations. These may be useful in the application of Si isotopes in phytoliths to archaeological and palaeoenvironmental contexts

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Section: Resultsmentioning

confidence: 99%

Macromolecule mediated bioinspired silica synthesis using a diol-modified silane precursor

et al. 2005

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“…The same constant decline in activity (slope: Ϫ4.8 nmol͞unit) was observed in the natSil-1A͞ natSil-2 system throughout the entire natSil-2 concentration range, suggesting that inhibition in both systems is caused by the same molecular mechanism. If so, the inhibitory effect of the polyanionic natSil-2 molecules is likely exerted by means of electrostatic shielding of the polycationic polyamine chains, because these represent the common structural elements of LCPA and natSil-1A, and polyamines are known to catalyze silica formation (10,11,22,23). Thus, the high negative charge density of natSil-2 appears to be an essential feature for regulating the silica precipitation activities of natSil-1A and LCPA.…”

Section: Resultsmentioning

confidence: 99%

Biosilica formation in diatoms: Characterization of native silaffin-2 and its role in silica morphogenesis

Poulsen

Sumper

Kröger

2003

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

321

303

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The biological formation of inorganic materials with complex form (biominerals) is a widespread phenomenon in nature, yet the molecular mechanisms underlying biomineral morphogenesis are not well understood. Among the most fascinating examples of biomineral structures are the intricately patterned, silicified cell walls of diatoms, which contain tightly associated organic macromolecules. From diatom biosilica a highly polyanionic phosphoprotein, termed native silaffin-2 (natSil-2), was isolated that carries unconventional amino acid modifications. natSil-2 lacked intrinsic silica formation activity but was able to regulate the activities of the previously characterized silica-forming biomolecules natSil-1A and long-chain polyamines. Combining natSil-2 and natSil-1A (or long-chain polyamines) generated an organic matrix that mediated precipitation of porous silica within minutes after the addition of silicic acid. Remarkably, the precipitate displayed pore sizes in the range 100 -1000 nm, which is characteristic for diatom biosilica nanopatterns.T he biological formation of intracellular or extracellular skeletons made of amorphous hydrated SiO 2 (biosilica) is relatively frequent among the protists and also occurs in many higher plants (1, 2). To date the organic molecules involved in biosilica formation have mainly been studied in sponges and diatoms (3). From the silica spicules of the sponge Thetya aurantia, proteaselike proteins termed silicateins were characterized that catalyze silica formation from tetraethoxysilane in vitro (4, 5). Diatoms are unicellular algae that have the extraordinary capability to produce an enormous variety of biosilica structures (6). Each diatom species is characterized by a specific biosilica cell wall that contains regularly arranged slits or pores in the size range between 10 and 1,000 nm (nanopatterned biosilica). Biosilica morphogenesis takes place inside the diatom cell within a specialized membrane-bound compartment termed the silica deposition vesicle (SDV). It has been postulated that the SDV contains a matrix of organic macromolecules that not only regulate silica formation but also act as templates to mediate biosilica nanopatterning (7-9). Insight into the nature of this organic matrix has been gained through the characterization of diatom biosilica-associated peptides (silaffins) and long-chain polyamines (LCPA), both of which accelerate silica formation from a silicic acid solution in vitro (10-12). Although native silaffin-1A (natSil-1A) and LCPA, respectively, mediate the formation of unusual silica structures in vitro (networks of irregularly shaped silica bands and large spherical silica particles) (11, 12), none of these are akin to diatom biosilica nanopatterns.Recently, it was shown that phosphorylation of natSil-1A is essential for silica formation activity (12), leading to the speculation that phosphorylated components may be generally important for biosilica morphogenesis. Therefore, a search for additional silica-associated phosphoproteins, which are able...

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“…Building on the recent discovery that both natural [63] and synthetic polyamines [64,65] catalyze the hydrolysis and condensation of silica precursors under ambient conditions, we developed a novel approach for templating 3D hybrid silica-organic structures that combines direct ink writing with biomimetic silicification. [25] These structures may be considered as synthetic analogs to naturally occurring diatom frustules.…”

Section: D Polyelectrolyte Scaffolds: Templates For Biomimetic Minermentioning

confidence: 99%

Direct Ink Writing of 3D Functional Materials

2006

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Cited by 91 publications

References 14 publications

Macromolecule mediated bioinspired silica synthesis using a diol-modified silane precursor

Macromolecule mediated bioinspired silica synthesis using a diol-modified silane precursor

Biosilica formation in diatoms: Characterization of native silaffin-2 and its role in silica morphogenesis

Direct Ink Writing of 3D Functional Materials

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