目的 制备血管内皮生长因子受体(VEGFR)-2靶向磁共振(MR)分子探针,探讨其对肝癌细胞的特异性靶向作用.方法 采用共沉淀法制备超顺磁性氧化铁(SPIO),用壳聚糖对其表面进行修饰,耦联anti-VEGFR2抗体,制备VEGFR-2靶向MR分子探针(anti-VEGFR2-CS@SPION),以未修饰的SPIO纳米粒作为对照组.DLS法测量粒径大小、分布及Zeta电位,3.0T MR检测T2弛豫率.MTT法评价探针的安全性,通过激光共聚焦显微镜检测以及普鲁士蓝染色的方法验证探针与肝癌细胞结合的特异性.3.0T MR观察探针的体外MR成像能力.结果 SPIO和anti-VEGFR2-CS@SPION的粒径分别为 20.6 nm和38.4 nm;Zeta电位分别为-(20.3±1.32)mV、(3.58±1.28)mV.T2弛豫率分别为0.179×10.6 M.-1S.-1、0.201×10.6 M.-1S.-1.细胞毒性实验表明探针在高浓度下对细胞没有毒性;激光共聚焦显微镜检测显示,抗体探针与HepG2细胞特异性结合;anti-VEGFR2-CS@SPION与HepG2细胞孵育后经普鲁士蓝染色,细胞内见较多的蓝染颗粒,而单纯SPIO组细胞内未见蓝色颗粒.体外MR成像显示,anti-VEGFR2-CS@SPION组、单纯SPIO组和空白对照组的T2值分别为(55.6± 1.4)ms、(99.8±0.77)ms和(110.8±0.95)ms,差异有统计学意义(F=317.547,P<0.01).结论 壳聚糖修饰和SPIO标记的anti-VEGFR2抗体探针具有良好的生物学特性和体外肝癌细胞MR显像能力.%Objective To prepare a targeting MR molecular probe with vascular endothelial growth factor receptor(VEGFR)-2, to determine the specific targeting function in human hepatoma cell.Methods The superparamagnetic iron oxide nanoparticles was prepared by coprecipitation methods, then the VEGFR-2-loaded MR molecular probe waS prepared by modifying SPIO with chitosan in surface and coupling anti-VEGFR2.The SPIO nanoparticles with unmodified was treated as control group.The particle size, distributed and Zeta potential were tested by DLS, its T2 relaxivity rate was tested by 3.0T MR.The security of probe was determined by MTT assay.The combination probe in HepG2 cell was detected by laser confocal microscopy.Results The particle sizes of SPIO and anti-VEGFR2-CS@SPION were 20.6 nm and 38.4 nm respectiviey, the Zeta potentials were (20.3±1.32) mV and (3.58±1.28) mV respectively, and the T2 relaxivity rates were 0.179×10.6 M.-1S.-1 and 0.201×10.6 M.-1S.-1 respectively.The laser confocal microscopy showed HepG2 cell specific binding with antibody probe.More blue-stained particles appeared in cells.But only few blue-stained particles appeared in control group.T2 values of anti-VEGFR2-CS@SPION, simple SPIO and empty control groups were (55.6± 1.4) ms, (99.8±0.77) ms and (110.8±0.95) ms respectively, there were significant differences (F=317.547,P<0.01) between them.Conclusions The anti-VEGFR2 molecular probe modified by chitosan and labeled by SPIO has good biological characteristics and vitro MR imaging for hepatoma cell.
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