中文摘要：

目的：用原子力显微镜（AFM）从分子水平、可视化角度研究纳米金（GNP）与血管内皮生长因子（VEGF165）的分子作用。方法：GNP与VEGF165作用前后,用AFM表征粒子大小和形貌,光谱学检测GNP紫外吸收光谱变化,粒径分析仪检测粒径分布变化;用VEGF165刺激无血清培养液的人脐静脉内皮细胞（HUVECs）增殖,在GNP干预前后,用AFM观察HUVECs细胞表面超微结构变化。MTT法观察纳米金对HUVECs增殖的影响。结果：GNP与VEGF165作用后,其吸收峰发生红移;粒径分析表明GNP粒径的主要分布从20 nm变成30 nm;AFM表征下,单个GNP粒径22.05 nm±1.52 nm,呈椭圆形,边界清晰,加入VEGF165后,平均粒径变成33.91 nm±2.61 nm,边界模糊,形状不甚规则,表明GNP与VEGF165结合;在AFM观察到VEGF165作用的HUVECs细胞出现伪足、细胞膜孔洞、细胞膜颗粒化和细胞连接增多等表现,而GNP可以明显抑制这一现象,MTT法表明GNP抑制VEGF165介导的HUVECs增殖。结论：GNP可与VEGF165通过化学键连接,形成以GNP为核、VEGF165为壳的GNP-VEGF165复合物,使VEGF165与其受体结合的位点失活或被阻断,抑制VEGF165的信号转导,从而抑制HUVECs增殖。

英文摘要：

AIM：To investigate the molecular interaction between gold nanoparticles（GNP） and vascular endothelial growth factor 165（VEGF165） under atomic force microscope（AFM）.METHODS： Before and after incubation with VEGF165,GNP were screened by integrated tools including AFM,ultraviolet-visible absorption spectroscopy and particle size analysis under near-physiological condition.In addition,GNP at different concentrations were incubated with VEGF165,then added to starved human umbilical vein endothelial cells（HUVECs）.The ultrastructural changes of HUVECs surface were examined by AFM.The effects of GNP on the growth of HUVECs were assessed by MTT assay.RESULTS： After treated with VEGF165,the GNP absorption peak revealed a slight red shift,and the size distribution of GNP was increased from 20 nm to 30 nm.By AFM imaging,the diameter of GNP was（22.05±1.52） nm in average while the average diameter of GNP-VEGF165 was（33.91±2.61） nm.Binding of GNP and VEGF165,and the formation of GNP-VEGF165 core-shell complex were indicated by the AFM imaging.AFM screening showed the changes of ultrastructure on HUVECs surface.The group of VEGF165 displayed the signs of cell proliferation.Granulation of cell surface,increase in cell-to-cell contact,formation of pseudopodia and appearance of membranes pores were all observed.The proliferation of HUVECs was inhibited by GNP with MTT assay.CONCLUSION： GNP bind to VEGF165 through chemical bonds to block or inactivate the receptor binding sites of VEGF165.Therefore,GNP inhibit VEGF165-induced proliferation of HUVECs.