| With the research development in the field of biomedicine and bioengineering, people are exploring various functional polymer microspheres, because of its peculiar magnetic response, functionalized and broad application prospects, which can serve as smart or intelligent tools for drug delivery, biomacromolecules purification, biosensor and enzyme immobilization, etc. Magnetic polymer microsphere has been fully developed as a new functional material in recent decades. Magnetic polymer microsphere is a kind of hybrid microsphere with magnetic property, which is composed of polymer and inorganic magnetic particles. The main advantage of magnetic polymeric microspheres over conventional polymeric microspheres is that, because of their super-paramagnetic properties, they can be rapidly separated from solution under magnetic field, which proposes a new approach for biological separation and detection, also brings new direction of development for researching functional materials.Based on the research background and the development trend of magnetic polymer microspheres, the research interest of this work focused in the preparation, characterization and properties for controlled release examination of magnetic polymer microspheres, which involves in four parts, i.e. the preparation and surface modification of magnetic microspheres, preparation of core-shell Fe3O4SiO2particles and preparation of magnetic polymer microspheres with super-paramagnetic. Finally, we used the functional magnetic polymer microspheres in the drug release research. The results of each part are listed as follows:1. Magnetite nanoparticles were prepared by chemical co-precipitation process. By modifying as-prepared super-paramagnetic magnetite nanoparticles with citric acid aqueous solution, stable magnetic fluid was obtained. Using the modified magnetic nanoparticles as seeds, core-shell structure silica-coated magnetite nanoparticles (Fe3O4/SiO2) were prepared via Stober method. Furtherly, the composite particles were characterized by FT-IR, XRD, TEM, EDX and VSM, it can be confirmed we prepared core-shell composite particles with super-paramagnetic successfully.2. By treating silica-coated magnetite nanoparticles with (3-aminopropyl) triethoxysilane (APTES) by a silanization reaction, amino-functionalized nanoparticles were prepared. And its affinity with organic matter was improved. At the same time, β-cyclodextrin was modified with maleic anhydride (MAH), carboxylic β-cyclodextrin was obtained. Fe3O4SiO2/β-CD magnetic polymer microspheres were prepared via the reaction between-NH2and-COOH. The obtained nanoparticles were characterized by TEM, laser particle size analyzer and VSM, and the results showed that the microspheres had an average size of120nm. The magnetic polymer microspheres had good distribution in aqueous solution, and exhibited good magnetic response.3. The invitro controlled release examination based on caffeine as the model drug and magnetic polymer microspheres Fe3O4SiO2/β-CD as the carrier, we researched the release rate in pH=7.4buffer solution and environmental stability. The results showed that loading efficiency was28.83%, had a significant release behaviour and good environmental stability. It can be confirmed that Fe3O4SiO2/β-CD magnetic polymer microspheres is a suitable drug carrier for controlled release. |
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