| In the past decade, nanomaterials have become a hotspot of research with the rapid progress of nanoscience and nanotechnology. Quantum dots (QDs) and magnetic nanoparticles are two representative ones of them. Fluorescent labeling and magnetic separation are two important and frequently-used techniques which have been widely applied in biomedical research. QDs have extensive application prospect due to their excellent fluorescent characteristics, such as multicolor emissions under single excitation light, size- and composition-tunable emission, high levels of brightness and photostability and so on. Magnetic nanoparticles could be directionally moved under extra-applied magnetic field because of their magnetic-orienting property and controllability. So, they were widely used for magnetic separation of the target from biological sample, targeting drug delivery and hyperthermia therapy. However, the single-functionality limits their application in complex samples, such as the simultaneous recognition and separation of specific components. Then, the fabrication and application of multifunctional nanomaterials has attracted much attention of researchers. Here, fluorescent-magnetic-multifunctional nanospheres were fabricated based on quantum dots and magnetic nanoparticles with poly(styrene/acrylamide) copolymer nanospheres as the template. After modified with different bioprobes, they were used for the mono-or multi-component analysis. This thesis report works as follows:(1) Fluorescent-magnetic-bifunctional nanospheres were fabricated by improving the present method. The number of quantum dots and magnetic nanoparticles embedded in each sphere were determined by viscosity analysis and atomic emission analysis. A fter the immobilization of lectins on the surface of spheres, the attached number of lectins on each sphere was calculated with fluorescence analysis and the as-constructed fluorescent-magnetic-biotargeted nanospheres were used for recognition and separation of A549 cells.(2) A set of fluorescent, magnetic, dual-encoded multifunctional bioprobes were constructed by co-embedding different-sized quantum dots and varying amounts of magnetic nanoparticles into swollen poly(styrene/acrylamide) copolymer nanospheres. After being functionalized, they were used to simultaneously recognize and selectively separate three kinds of lectins from a complex sample.(3) A reliable method for fabricate fluorescent, magnetic, dual-encoded nanospheres was introduced with layer-by-layer selfassembly of quantum dots and magnetic nanoparticles on the surface of poly(styrene/acrylamide) copolymer nanospheres. With this method, dualencoded nanospheres could be obtained with different fluorescent emissions and magnetic response by simply turning the coating amounts of QDs and magnetic nanoparticles as well as the size of QDs. This method was proven to be controllable and repeatable, and the dualencoded nanospheres were fabricated with good monodispersity and uniform particle size.(4) Base on the biotin-avidin system, the reaction kinetics of fluorescein isothiocyanate-labeled streptavidin on the surface of poly(styrene/acrylamide) copolymer nanospheres with free biotin and biotin attached onto different-sized spheres were investigated. Under certain conditions, the reaction extent could reach 90% within five minutes, which indicated that poly(styrene/acrylamide) copolymer nanospheres-based rapid detection of biomolecule, virus, bacterium and cell was theoretically feasible. |
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