用于磁共振造影的纳米磁性微粒的制备与特性研究

Preparation and Characteristics of Nanoparticle Used as the Contrast Agent for Abdomen MRI

目的:制备出磁响应性强、粒径小、分布均匀、且表面包覆一层助悬剂的磁性纳米微粒,为腹部磁共振造影提供一种新型材料。方法:用三氧化二铁作为磁性原料,羧甲基纤维素钠和黄原胶为助悬剂,水为基载液,利用研磨法制备出纳米磁性微粒。通过扫描电镜和原子力显微镜观察微粒的形态和大小,用磁强计检测微粒的磁响应性。结果:该法制备的包覆有助悬剂的三氧化二铁磁性微粒多呈球形,粒径为纳米级。常温下密封保存3个月性质不改变。在外加场强为104Oe、外部温度为18℃的条件下微粒的磁响应强度为(26.0±1.1)emu/g,撤除磁场时剩磁为零,显示微粒具有超顺磁性。结论:用该法制备的磁性微粒,具有有效粒径小、磁响应性好、不团聚、不沉降、且服用安全的优点,可作为一种新型磁共振口服造影剂,用于诊断胃肠道病变。

Objective： To prepare a kind of synthesizing magnetic particles which have good magnetic property, small size, and coating suspending agents on the surface, which to be used in contrast agent for abdomen magnetic resonance imaging （MRI）. Methods： With Fe2O3 as the major materials, sodium carboxymethylcellulose （CMC-Na） and xanthan gum as surfactant prepared the nanoparticles by micronization technology.The size and shape of the particles were verified by scanning elcctron microscope （SEM）. The morphology was investigated by atomic force microscope （AFM）. And the magnetic property was evaluated by magnetometer. Results ： Most of the nanoparticles showed shape of sphere, as indicated that the nanoparticles were tiny. The properties had kept invariable in the nogrmal temperature for three months. The magnetic response was （26.0±1.1） emu/g in a magnetic field of 10^4Oe and the remanence was zero without it, suggesting the nanoparticles＇ superparamagnetism. Conclusion： The nanoparticles have the advantages of small size, good magnetic property, no settlement, no agglomeration and no obvious toxicity. These magnetic particles can be used as the contrast agent for abdomen MRI to detect gastrointestinal disease.