Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
Anal Chim Acta. 2014 Jan 31;810:79-85. doi: 10.1016/j.aca.2013.12.005. Epub 2013 Dec 11.
Here we report the characterization of an electrochemical mercury (Hg(2+)) sensor constructed with a methylene blue (MB)-modified and thymine-containing linear DNA probe. Similar to the linear probe electrochemical DNA sensor, the resultant sensor behaved as a "signal-off" sensor in alternating current voltammetry and cyclic voltammetry. However, depending on the applied frequency or pulse width, the sensor can behave as either a "signal-off" or "signal-on" sensor in square wave voltammetry (SWV) and differential pulse voltammetry (DPV). In SWV, the sensor showed "signal-on" behavior at low frequencies and "signal-off" behavior at high frequencies. In DPV, the sensor showed "signal-off" behavior at short pulse widths and "signal-on" behavior at long pulse widths. Independent of the sensor interrogation technique, the limit of detection was found to be 10nM, with a linear dynamic range between 10nM and 500nM. In addition, the sensor responded to Hg(2+) rather rapidly; majority of the signal change occurred in <20min. Overall, the sensor retains all the characteristics of this class of sensors; it is reagentless, reusable, sensitive, specific and selective. This study also highlights the feasibility of using a MB-modified probe for real-time sensing of Hg(2+), which has not been previously reported. More importantly, the observed "switching" behavior in SWV and DPV is potentially generalizable and should be applicable to most sensors in this class of dynamics-based electrochemical biosensors.
在这里，我们报告了一种基于亚甲基蓝（MB）修饰和含胸腺嘧啶的线性 DNA 探针构建的电化学汞（Hg(2+)）传感器的特性。与线性探针电化学 DNA 传感器类似，所得传感器在交流伏安法和循环伏安法中表现为“信号关闭”传感器。然而，根据施加的频率或脉冲宽度，传感器在方波伏安法（SWV）和差分脉冲伏安法（DPV）中可以表现为“信号关闭”或“信号开启”传感器。在 SWV 中，传感器在低频下表现出“信号开启”行为，在高频下表现出“信号关闭”行为。在 DPV 中，传感器在短脉冲宽度下表现出“信号关闭”行为，在长脉冲宽度下表现出“信号开启”行为。无论传感器的检测技术如何，检测限均为 10nM，线性动态范围在 10nM 和 500nM 之间。此外，传感器对 Hg(2+)的响应非常迅速；大部分信号变化发生在<20min 内。总的来说，该传感器保留了此类传感器的所有特性；它无需试剂，可重复使用，灵敏、特异、选择性好。本研究还强调了使用 MB 修饰的探针实时感应 Hg(2+)的可行性，这在以前的研究中尚未报道过。更重要的是，在 SWV 和 DPV 中观察到的“切换”行为可能具有普遍性，并且应该适用于此类基于动力学的电化学生物传感器中的大多数传感器。
