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Silica Microspheres (silica + microsphere)

Distribution by Scientific Domains
Chemistry77%

Selected Abstracts

Preparation of C60-functionalized magnetic silica microspheres for the enrichment of low-concentration peptides and proteins for MALDI-TOF MS analysis

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 2 2009
Hemei Chen
Abstract In this work, for the first time, a novel C60-functionalized magnetic silica microsphere (designated C60-f-MS) was synthesized by radical polymerization of C60 molecules on the surface of magnetic silica microspheres. The resulting C60-f-MS microsphere has magnetite core and thin C60 modified silica shell, which endow them with useful magnetic responsivity and surface affinity toward low-concentration peptides and proteins. As a result of their excellent magnetic property, the synthesized C60-f-MS microspheres can be easily separated from sample solution without ultracentrifuge. The C60-f-MS microspheres were successfully applied to the enrichment of low-concentration peptides in tryptic protein digest and human urine via a MALDI-TOF MS analysis. Moreover, they were demonstrated to have enrichment efficiency for low-concentration proteins. Due to the novel materials maintaining excellent magnetic properties and admirable adsorption, the process of enrichment and desalting is very fast (only 5,min), convenient and efficient. As it has been demonstrated in the study, newly developed fullerene-derivatized magnetic silica materials are superior to those already available in the market. The facile and low-cost synthesis as well as the convenient and efficient enrichment process of the novel C60-f-MS microspheres makes it a promising candidate for isolation of low-concentration peptides and proteins even in complex biological samples such as serum, plasma, and urine or cell lysate. [source]

Microporous Silica Hollow Microspheres and Hollow Worm-Like Materials: A Simple Method for Their Synthesis and Their Application in Controlled Release

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2010
Mingwei Zhao
Abstract Hollow silica microspheres and hollow worm-like materials were synthesized by using a simple method with the aid of 1-dodecyl-3-methylimidazolium bromide (C12mimBr). Hollow silica microspheres were initially produced by utilizing the combination of evaporation and an emulsion template. At a longer mixing time, the microspheres fused to form hollow worm-like silica materials due to the fusion of the emulsion templates. The resultant silica materials were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and nitrogen adsorption/desorption. Both the hollow silica microspheres and the hollow worm-like materials are microporous. On the basis of experimental observations and the resulting products, a plausible formation mechanism is proposed. Preliminary tests demonstrate that the hollow silica microspheres and worm-like materials are capable of being loaded with Rhodamine B and releasing it, thus showing a great potential in controlled delivery applications. [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]

Preparation of C60-functionalized magnetic silica microspheres for the enrichment of low-concentration peptides and proteins for MALDI-TOF MS analysis

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 2 2009
Hemei Chen
Abstract In this work, for the first time, a novel C60-functionalized magnetic silica microsphere (designated C60-f-MS) was synthesized by radical polymerization of C60 molecules on the surface of magnetic silica microspheres. The resulting C60-f-MS microsphere has magnetite core and thin C60 modified silica shell, which endow them with useful magnetic responsivity and surface affinity toward low-concentration peptides and proteins. As a result of their excellent magnetic property, the synthesized C60-f-MS microspheres can be easily separated from sample solution without ultracentrifuge. The C60-f-MS microspheres were successfully applied to the enrichment of low-concentration peptides in tryptic protein digest and human urine via a MALDI-TOF MS analysis. Moreover, they were demonstrated to have enrichment efficiency for low-concentration proteins. Due to the novel materials maintaining excellent magnetic properties and admirable adsorption, the process of enrichment and desalting is very fast (only 5,min), convenient and efficient. As it has been demonstrated in the study, newly developed fullerene-derivatized magnetic silica materials are superior to those already available in the market. The facile and low-cost synthesis as well as the convenient and efficient enrichment process of the novel C60-f-MS microspheres makes it a promising candidate for isolation of low-concentration peptides and proteins even in complex biological samples such as serum, plasma, and urine or cell lysate. [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]

Efficient on-chip proteolysis system based on functionalized magnetic silica microspheres

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2007
Yan Li
Abstract An easily replaceable enzymatic microreactor has been fabricated based on the glass microchip with trypsin-immobilized magnetic silica microspheres (MS microspheres). Magnetic microspheres with small size (,300,nm in diameter) and high magnetic responsivity to magnetic field (68.2,emu/g) were synthesized and modified with tetraethyl orthosilicate (TEOS). Aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA) were then introduced to functionalize the MS microspheres for enzyme immobilization. Trypsin was stably immobilized onto the MS microspheres through the reaction of primary amines of the proteins with aldehyde groups on the MS microspheres. The trypsin-immobilized MS microspheres were then locally packed into the microchannel by the application of a strong field magnet to form an on-chip enzymatic microreactor. The digestion efficiency and reproducibility of the microreactor were demonstrated by using cytochrome c (Cyt-C) as a model protein. When compared with an incubation time of 12,h by free trypsin in the conventional digestion approach, proteins can be digested by the on-chip microreactor in several minutes. This microreactor was also successfully applied to the analysis of an RPLC fraction of the rat liver extract. This opens a route for its further application in top-down proteomic analysis. [source]

Synthesis of Novel Porous Magnetic Silica Microspheres as Adsorbents for Isolation of Genomic DNA

BIOTECHNOLOGY PROGRESS, Issue 2 2006
Zhichao Zhang
An improved procedure is described for preparation of novel mesoporous microspheres consisting of magnetic nanoparticles homogeneously dispersed in a silica matrix. The method is based on a three-step process, involving (i) formation of hematite/silica composite microspheres by urea-formaldehyde polymerization, (ii) calcination of the composite particles to remove the organic constituents, and (iii) in situ transformation of the iron oxide in the composites by hydrogen reductive reaction. The as-synthesized magnetite/silica composite microspheres were nearly monodisperse, mesoporous, and magnetizable, with as typical values an average diameter of 3.5 ,m, a surface area of 250 m2/g, a pore size of 6.03 nm, and a saturation magnetization of 9.82 emu/g. These magnetic particles were tested as adsorbents for isolation of genomic DNA from Saccharomyces cerevisiae cells and maize kernels. The results are quite encouraging as the magnetic particle based protocols lead to the extraction of genomic DNA with satisfactory integrity, yield, and purity. Being hydrophilic in nature, the porous magnetic silica microspheres are considered a good alternative to polystyrene-based magnetic particles for use in biomedical applications where nonspecific adsorption of biomolecules is to be minimized. [source]