title: Synthesis of novel porous magnetic silica microspheres as adsorbents for isolation of genomic DNA.
abstract: 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 microm, a surface area of 250 m(2)/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.
authors.affiliation: College of Pharmaceuticals and Biotechnology, Tianjin University, Tianjin 300072, China.
authors.forename: Zhichao
authors.initials: Z
authors.lastname: Zhang
authors.forename: Liming
authors.initials: L
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Ligong
authors.initials: L
authors.lastname: Chen
authors.forename: Qian-Hong
authors.initials: QH
authors.lastname: Wan
mesh_terms: D000327:Adsorption; D004247:DNA / Q000235:genetics / Q000302:isolation & purification*; D016681:Genome, Fungal / Q000235:genetics; D008280:Magnetics; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D009584:Nitrogen / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012822:Silicon Dioxide / Q000138:chemical synthesis / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D012822:Silicon Dioxide; D004247:DNA; D009584:Nitrogen