叶酸受体在正常组织上表达很少, 而在上皮源性的恶性肿瘤细胞膜表面高度表达。 文中以叶酸为稳定剂和包裹剂, 以硼氢化钠为还原剂, 简单快捷地制备出叶酸包裹的纳米金粒子(folic acid protected gold nanoparticles, FA-GNPs)作为靶向肿瘤探针。 紫外-可见吸收光谱测量, 透射电镜成像、 X射线光电子能谱分析以及细胞结合试验都表明, 这种纳米探针粒径分布在3～5 nm之间, 体系均一、 稳定, 而且在高盐环境(3.5% NaCl溶液)和高速离心(25 000 r·min-1)下均不会发生聚沉, 在肿瘤细胞检测等领域具有应用潜力。

Folate receptor (FR) is particularly upregulated in many epithelial cancer cells membrane and limited distribution is found in normal tissues. In the present work, the folic acid protected gold nanoparticles (FA-GNPs) were synthesized by a simple and quick method, in which chloroauric acid (HAuCl4) was reduced by sodium borohydride (NaBH4) in the presence of FA is used as stabilizer. UV-Visible spectroscopy and transmission electron microscopy (TEM) were used to characterize the shape and size distribution of the produced FA-GNPs. X-ray photoelectron spectroscopy and cell experiment were employed to confirm the immobilization of FA and GNPs. The results showed that FA-GNPs have a good size distribution in the 3~5 nm diameter range. Moreover, it is very stable even in solution with high concentration of salt (up to 3.5% NaCl), and even high speed centrifuges of 25 000 r·min-1 could not cause aggregation. The nanoparticles could be used to detect cancer cells.