Magnetic Composite Particles Of Bio-molecular Markers And The Preparation Of Magnetic Quantum Dots

Magnetic particles are defined as composite particles with nano- or micro-sized diameter which are composed of super-paramagnetic nanoparticles and inorganic or organic materials, through their interactions such as coating, crosslinking and modification. Due to the super-paramagnetic property, large ratio surface, biocompatibility, functional groups, as well as optical property, magnetic composite particles have been widely used in biomolecules labeling, bioseparation, biodetection and target therapy.The aim of this thesis was to explore the applications of new magnetic composite particles in molecules labeling, nucleic acids detection and cell sorting, synthesize magnetic quantum dots possessing dual features of fluorescence and magnetism, and lay solid foundation for the commercialization of magnetic composite particles in the future.Streptavidin GoldMag particles and amino terminal particles were prepared using GoldMag-A and amino terminal magnetic particles as carriers separately;The coupling efficiency and capacity of streptavidin, free biotin binding capacity, biotin labeled oligonucleiotide binding capacity for the two kinds of particles were studied as well, and their binding capacity is 6-7 times higher than that of Dynabeads? M-270 Streptavidin. Good experimental results of Streptavidin in the application of immunoassay, PCR products purification and mRNA purification were obtained.Goat anti mouse IgG were immobilized onto the surface of GoldMag-@ nanoparticles , 200μg goat anti mouse IgG can bind onto the particles surfaces, and it keeps good biological reactivity, their preliminary application in cells sorting was explored, and got a relatively good result, but there is still a long distance between commercialized cell separation kits.CdSe nanoparticles were synthesized by the method of high temperature decomposition. The size of the prepared CdSe nanoparticles was about 3 nm, their FWHM was 23 nm, and the quantum yield was about 20.6%. Fe3C>4@CdSe particles of micrometer grade with dual features of fluorescence and magnetism were synthesized by the interaction between thiol group and CdSe.