中文摘要：

目的测试纳米微粒在磁场导向下对微血管的栓塞效果。方法利用壳聚糖和Fe3O4磁流体合成顺磁性纳米微粒，利用体外模拟微血管观察磁粒在磁场下的凝聚，然后将纳米微粒静脉注射入大鼠并在脑区放置磁场．取脑组织后通过普鲁士蓝染色观察脑微血管栓塞情况。结果制得的顺磁性纳米微粒混悬液呈黑色，无絮状物或沉淀。电镜下测量微粒的平均有效粒径为15．3nm。其在外加磁场下能在体内外微血管内发生凝聚，栓塞微小血管。结论利用顺磁性纳米微粒进行磁靶向微血管栓塞是可行的，这可能成为一种治疗浅表肿瘤和脑血管疾病的新方法。

英文摘要：

Objective To test the role of paramagnetic nanoparticles in embolizing microvascular embolization under the guidance of magnetic field. Methods The paramagnetic nanoparticles were synthesized with chitosan and ferrofluid Fe3O4. The condensation of particles under magnetic field was observed in mimicked microvascular in vitro. The intravenous injection of nanoparticles was executed in rats and an external magnetic field （0.5T） was placed across their brains, which were sampled and stained by Prussian blue iron staining to observe microvascular embolization under microscope. Results The manufactured paramagnetic nanoparticle solution was black without floccules or precipitation. The mean diameter of the nanoparticle was 15.3 nm under electron microscope. These paramagnetic nanoparticles deposited in the microvessels in vitro and vivo, and resulted in microvascular embolization. Conclusions It is feasible to perform microvascular embolization by magnetic targeted therapy with paramagnetic nanoparticles, which may become a new method for superficial tumors and cerebrovascular diseases.