| Summary: | 碩士 === 國立臺灣大學 === 化學研究所 === 99 === In recent years, magnetic resonance imaging (MRI) plays an important role in bioimaging. Therefore, magnetic nanoparticles have attracted much attention as MRI contrast agents. Herein, we report a core shell bifunctional nanoparticle, MIO@SiO2-RITC (core: manganese iron oxide, MIO; shell: amorphous silica conjugated with RITC) with both fluorescent and magnetic properties for MR imaging. By tuning iron to manganese ratio, the nanoparticles possessed different saturated magnetization and relaxivities. SiO2 was selected for surface coating of IMO nanoparticles because dye molecules can be easily incorporated into silica shell. In addition, silica is quite biocompatible. The nanoparticles were characterized by TEM, ICP-MS, XRD and SQUID. In vivo MRI examination showed that contrast was enhanced in hippocampus, cerebellum, pituitary, submaxillary gland and kidneys of a rat in T1-weighted images, 72 h after tail vein injection.
Cell labeling is also an important field in the biomaterials application. For that purpose, we report another T2 contrast agent mFe3O4@MSN-RITC, having multiple magnetite nanoparticles attatched to a mesoporous silica nanoparticle, and simultaneously, the dye molecules conjugated into the mesoporous silica framework. The tri-functional nanoparticles possess magnetic, fluorescent property, and large surface area. In vitro examination, the cell uptake efficiency and cytotoxicity was evaluated by flow cytometry, fluorescence microscopy and WST assay. The results showed that the nanoparticles have high biocompatibility and uptake efficiency.
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