title: [Preparation of surface functional magnetic microspheres and their application in nucleic acid separation and enzyme immobilization].
abstract: OBJECTIVE
  To Prepare surface functional magnetic microspheres for the separation of vascular endothelial growth factor (VEGF) nucleic acid and lactase enzyme immobilization.
  
  
  METHODS
  Using suspension polymerization methods to copolymerize MA-styrene containing magnetite nanoparticles and GMA-styrene also containing magnetite nanoparticles, respectively. Both the carboxyl-modified magnetic microspheres and epoxy-modified magnetic microspheres were obtained. In addition, the chloromethyl-modified magnetic microspheres were prepared by seedy microemulsion. The magnetic microspheres bound with b-gamma IgG were determined by radioimmunoassay (RIA), and the separation of VEGF nucleic acid and lactase enzyme immobilization were performed by carboxyl-modified magnetic microspheres.
  
  
  RESULTS
  Transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS) and infrared (IR) spectra showed that the products of polymer magnetic microspheres were monodispersed and that the magnetic particles were uniformly distributed in the microsphere with special functional group on the surface of the microsphere. RIA showed that three kinds of magnetic microspheres could be bound with b-gamma IgG and the absorption of b-gamma IgG reached 75 micrograms/mg, especially for the carboxyl-modified magnetic microspheres. The carboxyl-modified magnetic microspheres can be used for the separation of VEGF nucleic acid by coupling with corresponding primer. Moreover, the immobilized enzyme was proportional to the amount of the carboxyl-modified magnetic microspheres.
  
  
  CONCLUSIONS
  The surface functional magnetic polymer microspheres can be bound with active bio-substance, and have a wide application prospect in the fields of biology and medicine.
authors.affiliation: Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237, China. yhzhu@ecust.edu.cn
authors.forename: Yi-hua
authors.initials: YH
authors.lastname: Zhu
authors.forename: Qiang-bin
authors.initials: QB
authors.lastname: Wang
authors.forename: Hong-chen
authors.initials: HC
authors.lastname: Gu
authors.forename: Sheng-lin
authors.initials: SL
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
mesh_terms: D000327:Adsorption; D016228:Endothelial Growth Factors / Q000737:chemistry*; D004800:Enzymes, Immobilized; D007074:Immunoglobulin G; D043322:Lactase / Q000378:metabolism; D008280:Magnetics; D008863:Microspheres; D036103:Nanotechnology; D009696:Nucleic Acids / Q000302:isolation & purification*; D010316:Particle Size
chemical_list: D016228:Endothelial Growth Factors; D004800:Enzymes, Immobilized; D007074:Immunoglobulin G; D009696:Nucleic Acids; D043322:Lactase