葡聚糖包裹的超顺磁性Fe3O4纳米颗粒用于MRI造影剂的研究

目的探讨葡聚糖包裹的超顺磁性Fe3O4纳米颗粒（dextran-coated superparamagnetic iron oxides nanoparticles，dextran／SPIONP）作为间质注射的MRI造影剂的可行性。方法应用界面共沉淀法，制备dex—tran／SPIONP，用透射电镜、能谱分析、X射线衍射、红外光谱测试、热重分析等方法对dextran／SPIONP的大小、磁性能等进行表征，并研究葡聚糖对SHONP的影响。然后，将dextran／SPIONP稀释成不同剂量，兔舌粘膜下间质注射后的不同时间段，切取前哨淋巴结，行核磁共振波谱分析，确定dextrart／SPIONP的最适剂量和最佳检测时间。结果dextran／SPIONP的平均直径为6～9nm，其表征与经典的共沉淀法制备的颗粒一致，具有超顺磁性，葡聚糖是影响SPIONP饱和磁化强度的主要因素。dextran／SPIONP用于间质注射的最适剂量为含铁量20μmol，最佳检测时间为注射后2Ah。结论用界面共沉淀法制备的dextran／SPIONP是一种适用于间质注射的MRI造影剂。

Study of dextran-coated superparamagnetic iron oxides nanoparticles as constrast agent

Objective To study the possibility of using dextran-coated superparamagnetic iron oxides nanoparticles (dextran/SPIONP) prepared by interfacial coprecipitation as a MRI constrast agent for interstitial injection.Methods Dextran/ SPIONP was prepared by interfacial coprecipitation.Dextran/SPIONP was characterized by transmission electron microscopy, spectrum analysis,X-ray diffraction,infrared spectrum,and thermal gravitational analysis.The effect of dextran for SPIONP was studied.Dextran/SPIONP was administrated into the tongue submucosa of a rabbit by interstitial injection after being diluted for different doses.Sentinel lymph nodes in different stages were harvested to determine the best dose and imaging timing of Dextran /SPIONP by nuclear magnetic resonance spectroscopy.Results Average diameters of dextran/SPIONP prepared by interfacial coprecipitation were from 6 to 9nm.Its characteristics with superparamagnetism are in accordance with those by classic coprecipitation. Dextran is the main factor to influence saturation magnetization of SPIONP.The best dose and imaging timing of dextran/SPIONP for interstitial inject were 20pjnol of iron and 24 hours after administration,respectively.Conclusions dextran /SPIONP prepared by interfacial coprecipitation is a MRI constrast agent for interstitial injection.