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Magnetite Particles (magnetite + particle)

Distribution by Scientific Domains

Chemistry	50%

Selected Abstracts

Highly Water-Dispersible Biocompatible Magnetite Particles with Low Cytotoxicity Stabilized by Citrate Groups,

ANGEWANDTE CHEMIE, Issue 32 2009
Jia Liu
Einheitliche Magnetit-Partikel mit stabilisierenden Citratgruppen wurden in einer Hochtemperatur-Solvothermalsynthese hergestellt. Die in Wasser dispergierbaren Partikel können leicht in Zellen eindringen, ohne diese zu zerstören, was für eine hervorragende Bioverträglichkeit spricht. Bei der Abtrennung von Peptiden wurde eine hohe Anreicherungsfähigkeit der Magnetit-Partikel beobachtet. [source]

Facile synthesis of C8 -functionalized magnetic silica microspheres for enrichment of low-concentration peptides for direct MALDI-TOF MS analysis

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2008
Hemei Chen
Abstract In this study, novel C8 -functionalized magnetic polymer microspheres were prepared by coating single submicron-sized magnetite particle with silica and subsequent modification with chloro (dimethyl) octylsilane. The resulting C8 -functionalized magnetic silica (C8 -f-M-S) microspheres exhibit well-defined magnetite-core-silica-shell structure and possess high content of magnetite, which endow them with high dispersibility and strong magnetic response. With their magnetic property, the synthesized C8 -f-M-S microspheres provide a convenient and efficient way for enrichment of low-abundance peptides from tryptic protein digest and human serum. The enriched peptides/proteins were subjected for MALDI-TOF MS analysis and the enrichment efficiency was documented. In a word, the facile synthesis and efficient enrichment process of the novel C8 -f-M-S microspheres make them promising candidates for isolation of peptides even in complex biological samples such as serum, plasma, and urine. [source]

Multifunctional Mesostructured Silica Microspheres from an Ultrasonic Aerosol Spray,

ADVANCED FUNCTIONAL MATERIALS, Issue 19 2008
Li Li
Abstract Multifunctional mesostructured silica microspheres are prepared using ultrasonic aerosol spray in conjunction with solvent evaporation-induced assembly. Rare earth ion,phenanthroline complexes, magnetite particles, photoacid generators, and pH-sensitive dyes are chosen as luminescent, magnetic, and photosensitive components. The incorporation of these functional components into mesostructured silica microspheres can be readily realized by dispersing them in the precursor solution of the aerosol spray process. Luminescent microspheres that can emit at multiple wavelengths when excited at a single wavelength are produced by the addition of multiple rare earth complexes into the precursor solution. The addition of magnetite particles leads to the production of magnetic luminescent microspheres. Photoacid generators and pH-sensitive dyes are further employed to produce magnetic photosensitive microspheres that can release acid and change color upon UV light illumination. Such multifunctional microspheres could have exciting potential for many optical and biotechnological applications, such as multiplexed labeling, diagnosis, simultaneous imaging and therapy, cell capture and separation, targeted delivery, and optical data storage. [source]

Bioaffinity magnetic reactor for peptide digestion followed by analysis using bottom-up shotgun proteomics strategy

JOURNAL OF SEPARATION SCIENCE, JSS, Issue 3 2008
Lucie Korecká
Abstract We report an efficient and streamlined way to improve the analysis and identification of peptides and proteins in complex mixtures of soluble proteins, cell lysates, etc. By using the shotgun proteomics methodology combined with bioaffinity purification we can remove or minimize the interference contamination of a complex tryptic digest and so avoid the time-consuming separation steps before the final MS analysis. We have proved that by means of enzymatic fragmentation (endoproteinases with Arg-C or/and Lys-C specificity) connected with the isolation of specific peptides we can obtain a simplified peptide mixture for easier identification of the entire protein. A new bioaffinity sorbent was developed for this purpose. Anhydrotrypsin (AHT), an inactive form of trypsin with an affinity for peptides with arginine (Arg) or lysine (Lys) at the C-terminus, was immobilized onto micro/nanoparticles with superparamagnetic properties (silica magnetite particles (SiMAG),Carboxyl, Chemicell, Germany). This AHT carrier with a determined binding capacity (26.8 nmol/mg of carrier) was tested with a model peptide, human neurotensin, and the resulting MS spectra confirmed the validity of this approach. [source]

Magnetite in ALH 84001: An origin by shock-induced thermal decomposition of iron carbonate

METEORITICS & PLANETARY SCIENCE, Issue 6 2003
Adrian J. BREARLEY
Transmission electron microscope studies of carbonate fragments embedded within feldspathic glass show that the fragments contain myriad, nanometer-sized magnetite particles with cuboid, irregular, and teardrop morphologies, frequently associated with voids. The fragments of carbonate must have been incorporated into the melt at temperatures of ,900°C, well above the upper thermal stability of siderite (FeCO3), which decomposes to produce magnetite and CO2 below ,450°C. These observations suggest that most, if not all, of the fine-grained magnetite associated with Fe-bearing carbonate in ALH 84001 could have been formed as result of the thermal decomposition of the siderite (FeCO3) component of the carbonate and is not due to biological activity. [source]

Cover Picture: Composite Silica Spheres with Magnetic and Luminescent Functionalities (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 4 2006
Mater.
Abstract Photographs of a colloidal dispersion of composite nanoparticles with magnetic and luminescent functionalities are shown (left, in column), which are schematically illustrated in the main image. As reported by Salgueiriño-Maceira and co-workers on p.,509, such functionalities are imparted by magnetic and semiconductor nanoparticles within a silica matrix. In the absence of a magnetic field the particles are uniformly dispersed, although they accumulate and can be dragged under the influence of a magnetic field. Their movement can be monitored by their photoluminescence. A new class of highly fluorescent, photostable, and magnetic core/shell nanoparticles in the submicrometer size range has been synthesized from a modified Stöber method combined with the layer-by-layer (LbL) assembly technique. Luminescent magnetic nanoparticles are prepared via two main steps. The first step involves controlled addition of tetraethoxysilane to a dispersion of Fe3O4/,-Fe2O3 nanoparticles, which are thereby homogeneously incorporated as cores into monodisperse silica spheres. The second step involves the LbL assembly of polyelectrolytes and luminescent CdTe quantum dots onto the surfaces of the silica-coated magnetite/maghemite particles, which are finally covered with an outer shell of silica. These spherical particles have a typical diameter of 220,±,10,nm and a saturation magnetization of 1.34,emu,g,1 at room temperature, and exhibit strong excitonic photoluminescence. Nanoparticles with such a core/shell architecture have the added benefit of providing a robust platform (the outer silica shell) for incorporating diverse functionalities into a single nanoparticle. [source]