磁性氧化铁高效磁共振造影剂的制备及应用

采用高温热分解法, 以乙酰丙酮铁为铁源, 生物相容性良好的聚乙二醇(PEG1000)作为溶剂、还原剂及修饰剂制备PEG修饰的氧化铁纳米粒子(PEG-SPIONs), 并研究其在小鼠体内的造影效果。X射线衍射(XRD)分析表明样品中含有Fe₃O₄晶相。透射电镜(TEM)结果显示, 合成的PEG-SPIONs形貌均一, 主要为等轴晶形, 纳米粒度及电位分析表明其表面呈负电性, 分散在水中的动力学粒径为20 nm。磁性能结果表明合成的PEG-SPIONs室温下具有超顺磁性, 并且具有较高的r₂/r₁值。细胞活性研究表明PEG-SPIONs具有较低的生物毒性, 体内的磁共振成像结果显示出PEG-SPIONs优异的对比增强效果, 说明PEG-SPIONs可以作为高效的T₂磁共振成像造影剂。

Synthesis and Application of Magnetic Iron Oxide Nanoparticles as High Efficiency Magnetic Resonance Imaging Contrast Agent

Iron oxide nanoparticles were synthesized by thermal decomposition of iron (III) acetylacetonate (Fe(acac)₃) in poly(ethylene glycol) (PEG), which was used as the solvent, reducing agent and modifying agent. X-ray powder diffraction (XRD) analysis indicates that the nanoparticles have magnetite crystal structure. The results of transmission electron microscope (TEM) show that the shapes of iron oxide nanoparticles coated with PEG are equiaxial with uniform morphology. Particles and Zeta potential analyses show that the surface of iron oxide nanoparticles is negatively charged, and their hydrodynamics size dispersed in deionized water is 20 nm. Iron oxide nanoparticles show superparamagnetic behavior at room temperature and high r₂/r₁ ratio. MTT studies show that PEG-SPIONs have low cytotoxicity. In vivo magnetic resonance imaging reveals their excellent contrast effects of the PEG-SPIONs. This work demonstrates that iron oxide nanoparticles coated with PEG can be excellent T₂ MRI contrast agents.