超顺磁性葡聚糖氧化铁纳米颗粒的研制及表征

目的 制备葡聚糖包被的超顺磁氧化铁（SPIO）纳米粒子，并对其主要物理性质和磁学性质进行研究。探讨它作为磁共振造影剂的可能性。方法 通过共沉淀法获得SPIO纳米粒子，分别采用透射电镜和光子相关光谱仪测定其粒径大小，利用邻苯二氮菲比色法测定铁的浓度，同时用核磁共振仪测定弛豫率等参数。结果 X-射线衍射分析确定所制备的葡聚糖磁性粒子主要为Fe3O4晶体，粒子体均粒径为85．9nm，氧化铁核心大小为15nm左右，具有超顺磁性，其弛豫率和质量磁饱和度分别达到0．1567mmol／ms和80emu／gFe。结论 所制备的SPIO粒子稳定，其物理性质表明其具有作为磁共振造影剂的特性。

Preparation and characterization of superparamagnetic iron oxide nanoparticles

OBJECTIVE: To determine the physical and magnetic properties of superparamagnetic iron oxide (SPIO) nanoparticle prepared in our laboratory and evaluate its possibility for use as contrast agents in magnetic resonance imaging (MRI). METHODS: The SPIO nanoparticle was obtained by means of classical coprecipitation in dextran solution and its size determined by electron microscopy and photon-correlation spectroscopy. The iron content was determined by phenanthroline photometry, and T(2) values as well as relaxivity evaluated with a clinical MR system at 1.5T. RESULTS: Dextran-coated magnetite particles with a hydrodynamic diameter of 85.9 nm were prepared. The iron core size was 15 nm and the formation of Fe(3)O(4) crystal in SPIO nanoparticles was confirmed by X-ray diffraction (XRD) analysis. These particles possessed some characteristics of superparamagnetic and show a smaller spin-spin relaxation, with relaxivity and saturation magnetization of 0.1567 mmol(-1)/ms(-1) and 80 emu/g Fe, respectively. CONCLUSIONS: A stable SPIO nanoparticle with a dextran coating have been developed, and in vitro evaluation of its physical and magnetic properties suggests its potential for use as the contrast agent in MRI.