To Study the Characteristics of Fe Oxide(Core)/Au(Shell) Nanoparticles by Ultra-low Field Nuclear Magnetic Resonance

• Main Authors: Yao-Wei Yeh, 葉曜緯
• Other Authors: Chiu-Hsien Wu
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/54639141759499487254

碩士 === 國立中興大學 === 物理學系所 === 103 === 　　The γ-Fe2O3(Core)/Au(Shell) magnetic nanoparticles have been synthesized by a reverse micelle method. The nanoparticles composed byγ-Fe2O3 and Au, as determined by spectrometer, x-ray diffraction (XRD) and transmission electron microscope (TEM). The average nanoparticle size is 28 ± 6.26 nm, as determined by laser diffraction particle size analyzer (DLS). The molarity of γ-Fe2O3 and Au is 0.1 mM and 0.138 mM in freshly synthesized γ-Fe2O3(Core)/Au(Shell) magnetic nanoparticles, as determined by inductivity coupled plasma-mass spectrometer (ICP-MS). And the saturation magnetization is 4.5 emu g-1, as determined by superconducting quantum interference device (SQUID). 　　Superparamagnetic iron oxide nanoparticles (Fe3O4) is used as T2 contrast agents in high field nuclear magnetic resonance (NMR) which the main magnetic field is over 1.5 T. The r2/r1 ratio of Fe3O4 is 422 in 7 T NMR. But r2/r1 ratio of γ-Fe2O3(Core)/Au(Shell) magnetic nanoparticles is 20.07. It may potentially be used as T1 agents at 7 T NMR. With the decrease of the main magnetic field to 100 μT, the r2/r1 ratio is also decreased to 0.43. It has stronger T1 contrast effect in low field NMR. Because of the Au shell, it will induce localized surface plasma resonance (LSPR) when using 532 nm green laser irradiate nanoparticles. LSPR caused the local magnetic field changing and promote the T1 contrast effect. It is expected to be applied to biomedical detection.