A Reusable DNA Single-Walled Carbon-Nanotube-Based Fluorescent Sensor for Highly Sensitive and Selective Detection of Ag+ and Cysteine in Aqueous Solutions
A Reusable DNA Single-Walled Carbon-Nanotube-Based Fluorescent Sensor for Highly Sensitive and Selective Detection of Ag+ and Cysteine in Aqueous Solutions
复制标题
一种可重复使用的基于 DNA 单壁碳纳米管的荧光传感器，用于高灵敏度和选择性检测水溶液中的银和半胱氨酸
DOI：
10.1002/chem.201000306
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发表时间：
2010-01-01
影响因子：
4.3
通讯作者：
Qu, Xiaogang
中科院分区：
文献类型：
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作者：
Zhao, Chao;Qu, Konggang;Qu, Xiaogang
在这里，我们报道了一种可重复使用的DNA单壁碳纳米管（SWNT）荧光传感器，用于高灵敏度和选择性检测水溶液中的银+和半胱氨酸（Cys）。由于其强大的pi-pi堆叠相互作用，swnt可以有效地猝灭染料标记单链DNA的荧光。然而，Ag+与Ag+孵育后，Ag+可以诱导由C-Ag+-C （C =胞嘧啶）配位化学介导的稳定双相形成，DNA熔融研究进一步证实了这一点。这削弱了DNA和单壁碳纳米管之间的相互作用，从而激活了传感器荧光。另一方面，由于Cys是一种强Ag+结合剂，它可以去除C-Ag+-C碱基对上的Ag+，并通过在SWNT周围重新包裹染料标记的寡核苷酸来使传感器荧光失活。这样，DNA/SWNT传感器的荧光信号开启和信号关闭可以分别用于检测水溶液中的Ag+和Cys。该传感平台对Ag+和Cys对其他金属离子和其他19种天然氨基酸具有较高的灵敏度和选择性，Ag+和Cys的检测限分别为1 nM和9.5 nM。基于这些结果，我们根据相同的传感机制，利用共价连接的SWNT-DNA偶联物构建了可重复使用的荧光传感器。没有关于使用SWNT-DNA检测Ag+和Cys的报道。该分析方法简单、有效、可重复使用，原则上可用于检测其他金属离子，方法是用选择性结合其他金属离子的其他天然或人工碱基取代C-C碱基对。
Here we report a reusable DNA single-walled carbon nanotube (SWNT)-based fluorescent sensor for highly sensitive and selective detection of Ag+ and cysteine (Cys) in aqueous solution. SWNTs can effectively quench the fluorescence of dye-labeled single-stranded DNA due to their strong pi-pi stacking interactions. However, upon incubation with Ag+, Ag+ can induce stable duplex formation mediated by C-Ag+-C (C = cytosine) coordination chemistry, which has been further confirmed by DNA melting studies. This weakens the interactions between DNA and SWNTs, and thus activates the sensor fluorescence. On the other hand, because Cys is a strong Ag+ binder, it can remove Ag+ from C-Ag+-C base pairs and deactivates the sensor fluorescence by rewrapping the dye-labeled oligonucleotides around the SWNT. In this way, the fluorescence signal-on and signal-off of a DNA/SWNT sensor can be used to detect aqueous Ag+ and Cys, respectively. This sensing platform exhibits high sensitivity and selectivity toward Ag+ and Cys versus other metal ions and the other 19 natural amino acids, with a limit of detection of 1 nM for Ag+ and 9.5 nM for Cys. Based on these results, we have constructed a reusable fluorescent sensor by using the covalent-linked SWNT-DNA conjugates according to the same sensing mechanism. There is no report on the use of SWNT-DNA assays for the detection of Ag+ and Cys. This assay is simple, effective, and reusable, and can in principle be used to detect other metal ions by substituting C-C base pairs with other native or artificial bases that selectively bind to other metal ions.