Preparation Of Nano-composite Ferrite And Its Application In Magnetic Resonance Imaging

Magnetic resonance imaging technology with its high spatial resolution,noninvasive, high tissue contrast occupies an important position in the field ofmolecular imaging technology.Research and development of relaxation of highefficiency, safe non-toxic novel MRI contrast agent to improve the resolution of theimage, the diagnostic sensitivity, enhanced signal contrast, becomes a challengingtask in the biomedical field in recent years.Ferrite magnetic nanoparticles withmagnetic properties of excellent received extensive attention in the development andapplication of magnetic resonance imaging, around the research hotspot of magneticnanoparticles mainly includes: preparation method improvement and optimization,material surface modification, core-shell structure of different combinations ofexploration and different nanoparticle assembly and integration.Magnetic ferrite nanocomposite material prepared in this paper high temperature pyrolysis method,preparation of mesoporous silica coated ferroferric oxide nano material prepared byhydrothermal method, and its application in MRI imaging.The full text consists offour chapters.The second chapter, we design and CoFe₂O₄@MFe₂O₄ferrite magneticnanocomposites were synthesized （M=Mn, Fe, Zn）, studied as MRI contrast agents inmagnetic resonance imaging applications.Its prominent characteristic is firstly bypyrolysis, the high boiling point solvent benzyl ether, with acetylacetone cobalt Co（acac）2and iron acetylacetonate Fe （acac）3as the cobalt and iron sources, oil amine,oleic acid as surfactant and stabilizer,1,2-sixteen alkyl glycol as the reducing agent,size even and controllable, good dispersion of particle size was about8nm CoFe₂O₄nanometer magnetic core is prepared, the saturation magnetization of58.4emu/g,with a higher rate of saturation magnetization.Continue to use the high seed coated byall kinds of ferrite shell MFe₂O₄（M=Mn, Fe, Zn）, based on the TEM diagram,particle size distribution, X ray photoelectron spectroscopy, analysis of hysteresis loop diagram representation indicating the material surface coating is successful.Thenusing dopamine ligand exchange method improved water solubility, indicated thatwater-soluble improve success through analysis of infrared spectra.Compared to studythe magnetic nano composite material cytotoxicity and magnetic resonance imagingeffect, which show that the obtained CoFe₂O₄@MFe₂O₄（M=Mn, Fe, Zn） with ferritenano composite material with high saturation magnetization, good biocompatibility,magnetic resonance angiography characteristics of obvious effect.The third chapter experiment using a synthetic route is simple and low cost（hydrothermal） Fe₃O₄magnetic nanoparticles prepared monodisperse, high saturationmagnetization with mesoporous structure of the particle size was about70nm, then N,N, N-,-1-sixteen alkyl three methyl bromide CTAB as the template, is Si acid esterhas been TEOS as silicon source hydrolysis, condensation, coated mesoporous silicashell using sol-gel method, preparation of core-shell structure Fe₃O₄@mSiO₂magnetic nanoparticle mesoporous structure with controllable morphologyPreparation of Fe₃O₄@mSiO₂nano composite material with uniform morphology,biocompatibility and other advantages of high saturation magnetization and goodbiological.