| The preparation, surface modification and basic application of multifunctional magnetic nanocomposites were systematically studied in this paper. Hydrophilic and lipophilic Fe3C>4 magnetic nanoparticles (MNPs) with different morphology, magnetic-fluorescent heterostructure (Fe3O4@ZnS and Fe3O4/CdSe), carbon nanotubes (CNTs)-based magnetic nanocomposites (Fe3O4/CNTs) and magnetic-fluorescent nanocomposites (ZnS/Fe3O4/CNTs), Re labeled functional magnetic nanocomposites for magnetic targeting hyperthermia and radiotherapy were prepared in this research. These nanocomposites have multifunction such as magnetic targeting, fluorescent visualization, hyperthermia, radiotherapy, medicine carrying and so on. This work laid a good foundation for the application of magnetic nanocomposites in magnetic targeted therapy of cancer. The details were described as below:Firstly, hydrophilic and lipophilic magnetic nanoparticles were prepared by the methods of polyols and high temperature pyrolysis, respectively. The synthesized products were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and so on. The spherical Fe3O4 MNPs were prepared without modifier. The Fe3O4 MNPs which belong to cubic system showed slight agglomeration and high magnetic responsibility and superparamagnetism. Monodisperse carboxylated Fe3O4 MNPs were obtained by adding polyacrylic acid (PAA) as modifier. When the reaction was moved to hydrothermal vessel, the obtained nanoparticles without adding modifier were agglomerated seriously. The Fe3O4 MNPs obtained by adding polyacrylic acid as modifier were agglomerated to secondary particles. When PEG was added, the growth of Fe3O4 MNPs become more completely with the increase of diameter and saturation magnetization. The lipophilic Fe3O4 MNPs was prepared by high temperature pyrolysis. The obtained Fe3O4 MNPs were modified with oleylamine, therefore the lipophilic Fe3O4 MNPs could be well dispersed in sealed n-hexane for several months. The morphology of Fe3O4 MNPs was changed with different volume ratio of oleic acid to oleylamine, it was more obvious under high temperature and high pressure. The morphology of Fe3O4 MNPs transformed from irregular to sphere, may be accompanied by the decrease of the ratio of oleic acid to oleylamine, on the contrary, the morphology of Fe3O4 MNPs transformed from irregular to quadrilateral and cubic, correspondingly, the saturation magnetization increased with the enlargement of the particle size.Secondly, the Fe3O4@ZnS, jujube pit and nailliked Fe3O4-CdSe heterostructure were obtained by thermal injection using lipophilic Fe3O4 MNPs as seed crystal. The synthesized products were characterized by XRD, TEM, FTIR, XPS, VSM, and so on. The results showed that the well dispersed Fe3O4@ZnS heterostructure was obtained and ZnS crystal was wurtzite. The jujube pit and nailliked Fe3O4-CdSe heterostructure were prepared by using CdO and stearic acid (SA) solution of CdO as precursors, respectively. The CdSe crystal in jujube pit Fe3O4-CdSe heterostructure was wurtzite. The CdSe nanocrystals grew along the c-axis of one side on the surface of Fe3O4 MNPs to form nail-liked structure due to the addition of SA. The nail liked Fe3O4-CdSe heterostructure consist of nail head (Fe3O4) and nail body (CdSe rod structure) which was hexagonal system. The saturation magnetization of Fe3O4@ZnS and Fe3O4-CdSe was decreased and the fluorescence was increased with the increased specific gravity of ZnS or CdSe. Thus the magnetism and fluorescence can be well controlled by adjusting the amount of the molar ratio of Fe3O4 and ZnS or CdSe.The magnetic and fluorescent ZnS/Fe3O4/CNTs nanocomposites were prepared by two steps of polyols and ethylene glycol method and characterized by XRD, TEM, FTIR, XPS, VSM, and so on. The surface of CNTs purified by integrated oxidation was clean without impurity. The active sites or oxygen-containing groups such as -COOH、-OH、-OSO3 which were produced by integrated oxidation promised the surface of CNTs with electronegativity for the attachment of Fe3O4 MNPs. When polyvinylpyrrolidone was used as dispersant, the Fe3O4 shell on the surface of CNTs was uniform and compact. The ZnS shell of wurtzite was uniformly dense on the surface of Fe3O4/CNTs nanocomposites which was modified with sodium dodecyl sulfonate beforehand. Therefor the surface of Fe3O4/CNTs was electronegative for the attachment of ZnS nanocrystles. The thickness of Fe3O4 and ZnS can be controlled by adjusting the amount of precursor, thus the magnetism and fluorescence can be well controlled.The fac-[Re(CO)3(H2O)3]+ obtained by reduction of NaReO4 with BH3-NH3 was used to label magnetic nanocomposites such as PAA modified Fe3O4、glutathione modified Fe3O4 and folic acid modified Fe3O4. The elements and valances of the synthesized products were characterized by XPS. The XPS pattern of fac-[Re(CO)3(H2O)3]+ showed that there were photoelectron lines of Re4、Re4d5、Re4d3、Re4p3、Re4p1、Ols and Cls. By another way, there was photoelectron line of carbonates indicating that carbonyl rhenium was prepared successfully, because there was no carbonous precursor in the reaction but CO. When Fe3O4-PAA was used as magnetic carrier, the XPS pattern showed little amount of Re in the nanocomposites indicating low label efficiency. When Fe3O4-GSH was used as magnetic carrier, XPS pattern showed the photoelectron lines of Re, but the valence of Re was +4 which was inconsistent with fac-[Re(CO)3(H2O)3]+. When Fe3O4-GSH-FA was used as magnetic carrier, XPS pattern showed strong photoelectron lines of Re and the binding energy of 4f7/2 illustrated that the valence of Re was+1, demonstrating that the magnetic nanoparticles were labeled by fac-[Re(CO)3(H2O)3]+ successfully. The obtained nanocomposites showed well magnetism which laid a good theoretical basis and foundation of experiment for the labeling of magnetic nanoparticles with 188Re. |
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