Fe3 O4 nanoparticles( NPs) modified with sodium citrate were prepared via chemical coprecipitation method and fetal bovine serum(FBS) could improve the dispersibility of Fe3O4 NPs in FBS solution(volume fraction≤5%) . At the temperature of 300 K, the saturation magnetization intensity of NPs reached 74. 86í10-3 A·m2/g(74. 86 emu/g); MRI T2 imaging of endothelial progenitor cells( EPCs) became better after being infected by 75 μg/mL of Fe3O4NPs and lentiviral vectors(LV); furthermore, EPCs could stably over express VEGF target gene. EPCs co-infected with Fe3 O4 NPs and LV, after being injected into caudal vein of focal cerebral ischemia rats could effectively promote angiogenesis. These results indicated the modified EPCs possessed both MRI tracing and angiogenesis, and therefore had potential application value in clinical therapy of cerebral ischemia.%采用化学共沉淀法制备了柠檬酸钠修饰Fe3O4纳米粒子(NPs),使用胎牛血清(FBS)改善Fe3O4 NPs的分散性.实验表明Fe3 O4 NPs尺寸均匀,且具有良好的稳定性, FBS浓度小于5%(体积分数)时, Fe3 O4 NPs无聚集沉淀；在300 K下,饱和磁化强度达到74.86×10-3 A·m2/g(74.86 emu/g)；核磁共振T2序列成像时,75μg/mL Fe3 O4 NPs与慢病毒载体( LV)共同标记内皮祖细胞( EPCs)成像效果良好；而且EPCs具有稳定过表达目的基因血管内皮生长因子( VEGF)的能力.利用Fe3 O4 NPs与LV共同感染EPCs,可有效促进大鼠血管生成.说明修饰后的EPCs兼具核磁共振成像( MRI)示踪和促血管生成双重功能.
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