Single strand DNA functionalized single wall carbon nanotubes as sensitive electrochemical labels for arsenite detection.
Single strand DNA functionalized single wall carbon nanotubes as sensitive electrochemical labels for arsenite detection.
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DOI：
10.1016/j.talanta.2015.03.040
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发表时间：
2015-08
期刊：
影响因子：
6.1
通讯作者：
Yonghong Wang;Ping Wang;Yiqiang Wang;Xiaoxiao He;Kemin Wang
中科院分区：
文献类型：
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作者：
Yonghong Wang;Ping Wang;Yiqiang Wang;Xiaoxiao He;Kemin Wang
本工作基于亚砷酸盐与单链DNA的结合能力和单壁碳纳米管的信号转导作用，建立了一种简单、灵敏的亚砷酸盐电化学检测方法。为了实现这一目的，首先通过π堆积将单链DNA包裹在单壁碳纳米管上，形成单链DNA/单壁碳纳米管复合体。在亚砷酸盐存在下，亚砷酸盐与单链DNA的G/T碱基结合强烈，降低了单链DNA与碳纳米管之间的π-π相互作用，导致一定量的单链DNA从络合物中解离出来。将分离出来的单壁碳纳米管选择性地组装在自组装单分子膜修饰的金电极上。然后，在SAM修饰的金电极上的单壁碳纳米管基本上恢复了几乎完全被SAM阻止的非均相电子转移。组装的单壁碳纳米管可以产生一种相当敏感和特异的信号转导策略，这种策略与亚砷酸盐的浓度有关。通过检测单壁碳纳米管介导的电流，亚砷酸盐浓度在0.5~10ppb范围内呈良好的线性关系，检出限为0.5ppb，具有良好的特异性和灵敏度。这种基于单壁碳纳米管的生物传感器为亚砷酸盐的检测创造了一种简单、灵敏、无放射性的方法。此外，本研究还提供了一种制备具有良好电化学性质的稳定生物传感器的新方法，被认为对电分析应用具有吸引力。
In this work, a simple and sensitive electrochemical strategy for arsenite detection based on the ability of arsenite bound to single-strand DNA (ssDNA) and the signal transduction of single wall carbon nanotubes (SWCNTs) is developed. To realize this purpose, the ssDNA/SWCNTs complexes were formed at first by making ssDNA wrapped around SWCNTs via π-stacking. In the presence of arsenite, the arsenite could strongly bind with the G/T bases of ssDNA and decrease the π–π interaction between ssDNA and SWCNTs, resulting in a certain amount of ssDNA dissociating from the complexes. The separated SWCNTs were selectively assembled on the self-assembled monolayer (SAM) modified Au electrode. Then the SWCNTs onto the SAM-modified Au electrode substantially restored heterogeneous electron transfer that was almost totally blocked by the SAM. The assembled SWCNTs could generate a considerably sensitive and specific tactic for signal transduction, which was related to the concentration of the arsenite. Through detecting the currents mediated by SWCNTs, a linear response to concentration of arsenite ranging from 0.5 to 10 ppb and a detection limit of 0.5 ppb was readily achieved with desirable specificity and sensitivity. Such a SWCNTs-based biosensor creates a simple, sensitive, nonradioactive route for detection of arsenite. In addition, this demonstration provides a new approach to fabrication of stable biosensors with favorable electrochemical properties believed to be appealing to electroanalytical applications.