Preparation And Study Of Composite Nanoparticles With Magnetic And Fluorescence Function

In recent years, monodisperse, non-toxic, tasteless and non-pollution colloidal silica nanoparticles have been extensively studied since many different functional groups can be embedded. Because of the dye-doped silica nanoparticles possessing of excellent photostability, chemical stability and bio compatibility and easy modification, they have been paid more attention. Silica matrix as a protective body of the dye can prevent the fluorophore from the influence of the solvent molecules, air oxidation and photobleaching.Magnetic nanoparticles (especially iron oxide) have been widely researched because of their potential application in biomedical field such as magnetic resonance imaging, separation of biochemical products, targeted drug delivery and so on. Compared with the conventional fluorescent nanoparticles, the composite nanoparticles have more advantages such as DN A hybridization analysis which can be done without the aid of solid carrier.In this thesis, the St?ber method was used to prepare fluorescent silica nanoparticles, magnetic silica nanoparticles and composite nanoparticles. The formation of silica was initiated by hydrolyzing TEOS (tetraethyl orthosilicate), catalyzed by ammonia. Compared to other methods, St?ber method is a relatively simple, time-saving procedure.This paper consists of four parts:Part 1:The development and applications of fluorescent nanoparticles, the emergence and development of nanotechnology, and the nature of nanomaterial and coumarin derivatives, the nature of the magnetic nanoparticles and their applications, are reviewed.Part 2:The fluorescence of 7-hydroxycoumarin in difference solvents and alkaline solution was researched. And the dye-doped nanoparticles were prepared by the St?ber method. And their fluorescence intensity was characterized and analyzed by fluorescence spectroscopy, the structure of nanoparticles was proved by IR spectroscopy, and by transmission electron microscopy their particle size was characterized and so on.Part 3:The nature of the 7-hydroxycoumarin 4-acetic acid was explored. By the St?ber method, the dye-doped nanoparticles were prepared. Also the nanocomposite particles were characterizated and analyzed by fluorescence spectroscopy, infrared spectroscopy, and transmission electron microscopy and so on.Part 4:At the first, by the chemical coprecipitation the iron oxide (Fe3O4) magnetic nanoparticles were synthesized, and then magnetic silica nanoparticles were prepared by St?ber method. At last, when the 7-HCA silica nano layers were deposited on its surface, the nanocomposite particles were got. Fluorescence spectroscopy, infrared spectroscopy, transmission electron microscopy and so on improved that the composite nanoparticles have luminescence and magnetism, and possess excellent photostability.