Silica biomimetic synthesis

Cha JN, Stucky GD, Morse DE, Deming TJ (2000) Biomimetic synthesis of ordered silica structures mediated by block copolypeptides. Nature 403 289-292... 

As mentioned earlier, biological systems have developed optimized strategies to design materials with elaborate nanostructures [6]. A straightforward approach to obtaining nanoparticles with controlled size and organization should therefore rely on so-called biomimetic syntheses where one aims to reproduce in vitro the natural processes of biomineralization. In this context, a first possibility is to extract and analyze the biological (macro)-molecules that are involved in these processes and to use them as templates for the formation of the same materials. Such an approach has been widely developed for calcium carbonate biomimetic synthesis [13]. In the case of oxide nanomaterials, the most studied system so far is the silica shell formed by diatoms [14]. 

A. Coupling reaction using ferric chloride (FeCl ) as oxidant 1, The polymerization from homo-monomer Compound 16 isolated from Vitis amurensis showed strong biological activity [7, 65] and its biomimetic synthesis was achieved as shown in Fig. (7). Oxidative coupling reaction of 1 with FeCU as oxidant produced an intermediate, ( )- -viniferin (107), by silica gel column chromatography. After acetylation, it was dehydrogenated by treatment with 2,3-dichloro-5,6- dicyano-1, 4-benzoquinone (DDQ) to afford an intermediate(108) and the desired compound 16 in 20% yield [7]. 

FIGURE 1.134 H NMR spectra (1) obtained for the original linear cationic poly(acrylamide-co-2-(dimethylamino) ethyl methacrylate, methyl chloride quatemized) (poly(AM-co-DMC)) with 30 mol% of DMC and (2) obtained for the hybrid copolymer-silica nanoparticles. (Adapted from J. Colloid Interface Sci., 338, Li, X., Yang, T., Gao, Q., Yuan, J., and Cheng, S., Biomimetic synthesis of copolymer-silica nanoparticles with tunable compositions and surface property, 99-104, 2009b. Copyright 2009, with permission from Elsevier.)... 

Li, X., Yang, T., Gao, Q., Yuan, J., and Cheng, S. 2009b. Biomimetic synthesis of copolymer-silica nanoparticles with tunable compositions and surface property. J. Colloid Interface Sci. 338 99-104. 

Chang, J.S., Kong, Z.L., Hwang, D.F. and Chang, K.L.B. (2006) Chitosan-catalyzed aggregation during the biomimetic synthesis of silica nanoparticles. Chemistry of Materials, 18, 702-7. 

Brunner, E. (2007) Biomimetic synthesis double-walled silica nanombes. Nature Materials, 6, 398-9. 

Brunner, E., Lutz, K., Sumper, M. Biomimetic synthesis of silica nanospheres depends on the aggregation and phase separation of polyamines in aqueous solution. Phys. Chem. Chem. Phys. 6, 854-857 (2004)... 

Shimizu, K. and Morse, D.E. (2000) The biological and biomimetic synthesis of silica and other polysdoxanes, in Biomineralization From Biology to Biotechnology and Medical Application (ed. E. Baeuerlein), Wiley-VCH, Weinheim, pp. 207-219. 

Roth, K.M., Zhou, Y., Yang, W. and Morse, D.E. (2005) Bifunctional small molecules are biomimetic catalysts for silica synthesis at neutral pH. Journal of the American Chemical Society, 127, 325-330. 

Furthermore, diatoms and radiolaria exert strict species-specific control over the patterns and pore sizes of the silica, which is precipitated at ambient conditions. Controlled industrial synthesis of silica, on the other hand, requires extreme pHs and/or temperatures. Biomimetic silica synthesis has, therefore, attracted much interest among materials scientists and phycologists for potential industrial applications, such as components of industrial separators, catalysts, and electronic devices.64-67... 

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