Liu Chi-Wei, Huang Chih-Ching, Chang Huan-Tsung
Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei, Taiwan.
Langmuir. 2008 Aug 5;24(15):8346-50. doi: 10.1021/la800589m. Epub 2008 Jun 26.
We have developed a new highly selective and sensitive technique for the detection of Hg(2+) using DNA-functionalized gold nanoparticles (Au NPs) and OliGreen. This system is the first that allows the detection of Hg(2+) based on the release of DNA molecules, induced by conformational changes on Au NP surfaces, and its sensitivity is highly dependent upon surface DNA density. When Hg(2+) ions interact with the thymidine units of the DNA molecules bound to the Au NPs through Au-S bonds, the conformations of these DNA derivatives change from linear to hairpin structures, causing the release of some of the DNA molecules from the surface of the Au NPs into the bulk solution to react with OliGreen. The fluorescence of OliGreen-DNA complexes increased with increasing concentration of Hg(2+), and Hg(2+) could be detected at concentrations as low as 25 nM. A linear correlation existed between the fluorescence intensity and the concentration of Hg(2+) over the range 0.05-2.5 microM (R(2) = 0.98). This simple and cost-effective probe was applied to determine the spiked Hg(2+) in the pond samples; the recoveries (96-102%) suggested low matrix interference and high sensitivity.
我们开发了一种使用DNA功能化金纳米颗粒（Au NPs）和OliGreen检测Hg(2+)的新型高选择性和灵敏技术。该系统是首个基于Au NP表面构象变化诱导DNA分子释放来检测Hg(2+)的系统，其灵敏度高度依赖于表面DNA密度。当Hg(2+)离子通过Au-S键与结合在Au NPs上的DNA分子的胸腺嘧啶单元相互作用时，这些DNA衍生物的构象从线性变为发夹结构，导致一些DNA分子从Au NPs表面释放到本体溶液中与OliGreen反应。OliGreen-DNA复合物的荧光随Hg(2+)浓度增加而增强，Hg(2+)浓度低至25 nM时即可检测到。在0.05 - 2.5 microM范围内，荧光强度与Hg(2+)浓度呈线性相关（R(2) = 0.98）。这种简单且经济高效的探针用于测定池塘样品中加标的Hg(2+)；回收率（96 - 102%）表明基质干扰低且灵敏度高。
