Surface-Enhanced Raman Scattering Chip for Femtomolar Detection of Mercuric Ion (II) by Ligand Exchange
Surface-Enhanced Raman Scattering Chip for Femtomolar Detection of Mercuric Ion (II) by Ligand Exchange
复制标题
通过配体交换飞摩尔检测汞离子 (II) 的表面增强拉曼散射芯片
DOI：
10.1021/ac303358w
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发表时间：
2013-03-19
影响因子：
7.4
通讯作者：
Zhang, Zhongping
中科院分区：
文献类型：
--
作者：
Du, Yuanxin;Liu, Renyong;Zhang, Zhongping
汞离子（Hg 2+）的化学传感技术已被广泛应用于各种传感材料和技术的研究。实现对金属离子的超灵敏但简单、快速和廉价的检测仍然是一个挑战。在这里，我们报告了一个表面增强拉曼散射（Sers）芯片的毫微微摩尔（fM）检测Hg 2+采用银包覆的金纳米粒子（Au@Ag NPs）与有机配体一起。4，4 '-联吡啶（Dpy）通过其与Ag纳米壳的双相互作用位点可以控制Au@Ag NPs的聚集，以产生强的拉曼热点和Sers读数。而Hg ~（2+）通过与Dpy的配位作用抑制了Au@Ag纳米粒子的聚集，从而使Dpy的Sers信号发生淬灭。在此基础上，通过在硅片上组装Au@Ag纳米颗粒，并进一步用Dpy修饰，制备了SEAS芯片。Dpy从芯片交换到Hg 2+水溶液液滴中导致Dpy的拉曼信号淬灭，响应于10 fM Hg 2+，这比美国环境保护局在饮用水中定义的极限低约6个数量级。每个测试使用的Sers芯片只需要一滴20 μ L的样品，并在类似的4分钟内完成。Sers芯片也已被应用到牛奶，果汁和湖水中的Hg 2+的定量。
The chemical sensing for the convenient detection of mercuric ion (II) (Hg2+) have been widely explored with the use of various sensing materials and techniques. It still remains a challenge to achieve ultrasensitive but simple, rapid, and inexpensive detection to metal ions. Here we report a surface-enhanced Raman scattering (SERS) chip for the femtomolar (fM) detection of Hg2+ by employing silver-coated gold nanoparticles (Au@Ag NPs) together with an organic ligand. 4,4'-Dipyridyl (Dpy) can control the aggregation of Au@Ag NPs via its dual interacting sites to Ag nanoshells to generate strong Raman hot spots and SERS readouts. However, the presence of Hg2+ can inhibit the aggregation of Au@Ag NPs by the coordination with Dpy, and as a result the SERS signals of Dpy are quenched. On the basis of these findings, a SEAS chip has been fabricated by the assembly of Au@Ag NPs on a piece of silicon wafer and the further modification with Dpy. The exchange of Dpy from the chip into the aqueous Hg2+ droplet results in the quenching of Raman signals of Dpy, responding to 10 fM Hg2+ that is about 6 orders of magnitude lower than the limit defined by the U.S. Environmental Protection Agency in drinkable water. Each test using the SERS chip only needs a droplet of 20 mu L sample and is accomplished within similar to 4 min. The SERS chip has also been applied to the quantification of Hg2+ in milk, juice, and lake water.