Research Of The Novel Preparation Of Magnetic Fluorescent Bifunctional Nanomaterials

Nanomaterials presents great value of science research and high potential for practical applications in many domains due to their unique electrical, optical and magnetic properties. Among various nanomaterials, magnetic nanoparticles Fe3O4, as a special kind of functional materials, have drawn wide attention in respect to the study of their preparation process and product properties. After varions modification of the surface of magnetic nanoparticles, the chemical stabilities and biocompatibility\ies can be enhanced effectively. QDs, namely, the semiconductor quantum dots, with excellent fluorescence quantum size effect, have been increasingly applied in the study of fluorescence energy transfer, fluorescence imaging and the preparation of fluorescent probes. However, with the rapid development of nanomaterials, single functional nanoparticles can’t meet the demand for practical biomedical application. It is an inevitable trend to combine magnetic with fluorescence properties. For the purpose of one step completion of fluorescence labeling and magnetic separation, an effective method is to prepare a kind of bifunctional nanocomposites in the way of connecting QDs to Fe3O4particles to solve the problem of separation. Above all, this is an issue of great significance. This article carry out the following research work:(1) CdTe QDs were prepared by the three-step colloidal method in water phase., which were then modified by hioglycolic acid. Meanwhile, the paperation of CdSe/CdS quantum dots with good fluorescent were carried out in oil phase with oleic acid and liquid paraffin as the solvent, and with hioglycolic acid as a stabilizer to convert oil phase quantum dots into water phase QDs. It is convenient for the following synthesis on account of carboxyl of the QDs surface. Different testing indicates that QDs not only have good dispersity but also strong fluorescence and stability.(2) Fe3+and Fe2+as raw materials, the Fe3O4nanoparticles were synthesized by coprecipitation method with NaOH precipitator. Afterwards, they were modified by polyethylene glycol to enhance homogeneity and dispersity. The Fe3O4nanoparticles as cores, were encapsulated by MOS with the method of reverse embedding to obtain Fe3O4/MOS. They were coated with functional hydroxy as a result, which improved their biocompatibility. Fe3O4/MOS were characterized by the infrared spectra and X-ray diffraction (XRD) spectra show that the MOS have successfully wrapped in Fe3O4outer layer, and the products are spherical, stable and superparamagnetic.(3) The successful connection of Fe3O4/MOS and Quantum dots first involved covalent bondings between hydroxy on the surface of Fe3O4/MOS and carboxyl on the surface of QDs, with EDC activator and DMAP catalyst. Bifunctional luminescent and magnetic nanoparticles was prepared at last. Through the overall characterization of Energy Disperse Spectroscopy (EDS), transmission electron microscope (TEM), fluorospectro photometer, infra-red spectrophotometer, ultraviolet spectrophotometer, fluorescence microscope and vibrating sample magnetometer. The results show that Fe3O4/MOS/QDs have excellent magnetic properties and good fluorescent and can be preserved; the average size of the products are around35nm.