Preparation Of Surface Functional Magnetic Microspheres And Their Application In Nucleic Acid Separation

Now with the research development in field of biomedicine and bioengineering, people are exploring various functional polymer microspheres which can serve as smart or intelligent tools for drug delivery,bi omacromolecules purification, biosensor and enzyme immobilization,etc. Based on the research background and the development trend of polymerm icrospheres,the research interest of this work focused in the preparation and primary application of functionalized magnetic polymer microspheres, which involves in five parts, i.e. the preparation and surface modification of magnetite nanoparticles, preparation of magnetite@silica particles, preparation and primary application of dual-responsive polymer microspheres which possess magnetically responsive and thermoresponsive properties, and preparation of fluorescence labeled dual-responsive polymer microspheres. The results of each part are listed as follows:(1) Well-defined silica-magnetite core-shell nanospheres were prepared via a modified sol–gel method. Sphere-like magnetite aggregates were obtained as cores of the final nanospheres by assembling in the presence of Tween 20. Characterization by transmission electron microscopy (TEM) showed spherical morphology of the nanospheres with controlled silica shell thickness from 9 to 30 nm, depending on the amount of tetraethoxysilane (TEOS) used. The nanospheres contained up to 41.7wt% magnetite with a saturation magnetization of 21.8 emu/g. Up to 35 mg/mg of the model biomolecule streptavidin (SA) could be bound covalently to the hydrophilic silica na(2)A layer of AEAPS encapsulating the particles with have a layer of SiO2 , then connect the Oligo(dT) with have linked by biotin to the particles with linked by SAv, Construct a paramagnetism RNA separation with can link the target RNA Specificitily, so we can separate and gather RNA effectively.(3)Iron oxide magnetic nanoparticles with biocomapatibility and functional coatings appropriate surface Chemistry approaches have been used for immobilization of cells,proteins,enzymes, nucleic acids through adsorption..The surface–modified magnetic nanopartieles have been widely used in biological and biomedical areas such as separation of genomic DNA, The isolation of genomic DNA from cells can be greatly simplified by manipulating magnetic bead-biomaterial conjugates with the appropriate magnetic fields.(4) The genomic DNAfrom cells were extracted with two methods separately.Then the ration of OD260 and OD280 was determined by ultraviolet spectrophotometer.The purity of the nucleic acid was calculated and the position of DNAsegments ing the gel was observed by agar sugar gel electrophoresis.Finally,genomic DNA with nanoparticles cannot use noxious reagents,it is a simple,rapid,and efficient methods for the isolation of DNA from a number of cellular sources.