新型磁共振造影剂介孔二氧化硅钆掺合纳米颗粒的研制

Synthesis and Characterization of Gd^(3+) Incorporated Mesoporous SiO_2 Nanoparticles,a New Magnetic Resonance Imaging Contrast Agent

【目的】研制一种新型顺磁性高的含钆纳米材料介孔二氧化硅钆掺合纳米颗粒(Gd-MCM-41),评估其应用于影像学诊断的可行性。【方法】将Gd掺合到MCM-41的介孔孔道中,制备含钆纳米材料Gd-MCM-41,透射电镜观察该纳米材料特征;X-射线能谱仪测量复合材料内的钆含量;0.5T核磁共振分析仪测定该材料的弛豫率R1、R2;1.5T磁共振成像系统观察其在Balb/c裸鼠体内和鼻咽癌CNE-2裸鼠移植瘤的分布特点。【结果】制备的含钆纳米颗粒呈圆球形,直径约80～150nm。X-射线能谱仪测量该复合材料内的钆含量(质量百分比)约2.89%。加入分散剂Tween研磨分散后,Gd-MCM-41在0.5T的纵向弛弛豫率R1、横向弛豫率R2分别为7.45mmol-1.L.S-1、10.97mmol-1.L.S-1,显著高于常规造影剂Gd-DTPA(R1,4.27mmol-1.L.S-1;R2,4.99mmol-1.L.S-1)。含钆纳米造影剂静脉注射后,1min胸主动脉信号强度明显增高,约30～60min达峰,随后信号强度渐降,该材料主要在肝脏分布和代谢,并使鼻咽癌CNE-2裸鼠移植瘤在MR图像上较明显强化。【结论】本研究成功制备了含钆纳米材料的新型磁共振造影剂,在肿瘤局部聚集,为进一步研究和应用于影像诊断奠定了基础。

[Objective] To prepare Gd3＋ incorporated mesoporous SiO2 nanoparticles（Gd-MCM-41）,a gadolinium-containing nanometer particles with high paramagnetism,as a novel MRI contrast agent.[Methods] Gadolinium was incorporated into a mesoporous silica nanoparticle MCM-41 to prepare Gd-MCM-41.The superficial syndrome,Gd loading and magnetic susceptibility of the Gd-incorporated material were detected by high-resolution transmission electron micrographs,energy dispersive X-ray spectrometer and 0.5T NMR analyzer,respectively.The distribution of this nanosized particles in Balb/c nude mice and nasopharyngeal carcinoma（NPC） xenografted CNE-2 tumors were analyzed using a 1.5 T MR scanner.[Results] The globular-shaped Gd-containing mesoporous nanoparticle was approximately 80 nm to 150 nm in diameter.This Gd-containing material has a Gd loading of 2.89 wt %.The particles dispersed with dispersant Tween have an R1 of 7.45 mmol-1·L·S-1 and R2 of 10.97 mmol-1·L·S-1 at 0.5 T respectively.After tail vein intravenous administration,the Gd-containing nanoparticles were mainly distributed in the liver,and the significant enhancement was demonstrated in NPC CNE-2 xenografted tumors.[Conclusion] A gadolinium-containing nanoparticle Gd-MCM-41 might be a novel nanoparticle contrast agent for magnetic resonance imaging.