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Silica Precursor (silica + precursor)

Distribution by Scientific Domains
Polymers and Materials Science100%

Selected Abstracts

Bottom-Up Synthesis of Biologically Active Multilayer Films Using Inkjet-Printed Templates

ADVANCED FUNCTIONAL MATERIALS, Issue 9 2010
Joshua D. Swartz
Abstract As a non-invasive, rapid prototyping technique, piezoelectric inkjet printing using the Dimatix Materials Printer (DMP) is incorporated to template 2D biologically active surfaces. In these studies, a bioinspired ink is synthesized and printed directly onto gold-coated silicon nitride substrates and into polymer-coated 96-well plates. Once deposited on a surface, these patterns are reacted with varying concentrations of a model enzyme glucose oxidase in the presence of a silica precursor, monosilicic acid. The reaction mechanism and order of reactant products within and along the patterns are shown to directly affect the integrity and overall microstructure of the biologically active films. Using profilometry measurements and scanning electron microscopy, a biologically active platform is optimized without significantly compromising the activity of the enzyme. In fact, enzyme activity, constrained within a thin film, is reported for the first time over variable reaction parameters. When compared to the enzyme free in solution, the immobilized enzyme is 25.9% active, where nearly 100% of the activity is retained after repeated usage. [source]

Highly Ordered Arrays of Mesoporous Silica Nanorods with Tunable Aspect Ratios from Block Copolymer Thin Films,

ADVANCED MATERIALS, Issue 4 2008
A. Chen
Highly ordered arrays of mesoporous silica nanorods with a tunable aspect ratio can be fabricated using PEOm - b -PMA(Az)n block copolymer thin films as templates. Together, penetration of the films by the silica precursor and the film thickness control the SiO2 nanorod growth, and heights of almost 200,nm can be achieved. Inside the SiO2 nanorods, mesochannels with a diameter of ,,2,nm are formed that are aligned along the longitudinal axis of the rod. [source]

High Rate Silicification of Peptide-Polymer Assemblies Toward Composite Nanotapes

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2008
Stefanie Kessel
Abstract Well-defined silica composite nanofibers are generated in a silicification process of self-assembled poly(ethylene oxide)-peptide nanotapes. Inspired by biological silica morphogenesis processes the nanotapes exhibit strong binding capabilities for silicic acid. Thus, pre-hydrolyzed tetramethoxysilane could be used as silica precursor. Very low concentrations (270 µM) and short contact times (10 s) are sufficient to form effectively integrated nano-composite tapes. [source]

Synthesis of PEOlated Fe3O4@SiO2 Nanoparticles via Bioinspired Silification for Magnetic Resonance Imaging

ADVANCED FUNCTIONAL MATERIALS, Issue 5 2010
Happy Tan
Abstract Inspired by the biosilification process, a highly benign synthesis strategy is successfully developed to synthesize PEOlated Fe3O4@SiO2 nanoparticles (PEOFSN) at room temperature and near-neutral pH. The success of such a strategy lies in the simultaneous encapsulation of Fe3O4 nanocrystals and silica precursors into the core of PEO-based polymeric micelles. The encapsulation results in the formation of a silica shell being confined to the interface between the core and corona of the Fe3O4 -nanocrystal-loaded polymeric micelles. Consequently, the surface of the Fe3O4@SiO2 nanoparticle is intrinsically covered by a layer of free PEO chains, which enable the PEOFSN to be colloidally stable not only at room temperature, but also upon incubation in the presence of proteins under physiological conditions. In addition, the silica shell formation does not cause any detrimental effects to the encapsulated Fe3O4 nanocrystals with respect to their size, morphology, crystallinity, and magnetic properties, as shown by their physicochemical behavior. The PEOFSN are shown to be good candidates for magnetic resonance imaging (MRI) contrast agents as demonstrated by the high r2/r1 ratio with long-term stability under high magnetic field, as well as the lack of cytotoxicity. [source]