Fundamental Science on Radioactive Geology and Exploration Technology Laboratory, East China Institute of Technology, Nanchang, Jiangxi 330013, China.
Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical College, 221004 Xuzhou, China.
Biosens Bioelectron. 2015 Feb 15;64:177-81. doi: 10.1016/j.bios.2014.09.001. Epub 2014 Sep 6.
We describe a novel signal-on electrochemical DNA (E-DNA) sensing platform based on target-catalyzed hairpin assembly. The thiolated modified molecular beacon 1 (MB1) was first immobilized onto the Au electrode (GE) surface and then target DNA hybridized to the MB1, the opened MB1 assembled with the ferrocene (Fc)-labeled molecular beacon 2 to displace the target DNA, which became available for the next cycle of MB1-target hybridization. Moreover, Fc was confined close to the GE surface for efficient electron transfer, resulting in a current signal. Eventually, each target strand went through many cycles, resulting in numerous Fcs confining close to the GE, which leaded to the current of Fc dramatically increase. The observed signal gain was sufficient to achieve a demonstrated detection limit of 0.74 fM, with a wide linear dynamic range from 10(-15) to 10(-10)M and discriminated mismatched DNA from perfect matched target DNA with a high selectivity. Thus, the proposed E-DNA sensor would have a wide range of sensor applications because it is enzyme-free and simple to perform.
我们描述了一种基于目标催化发夹组装的新型信号开启电化学 DNA（E-DNA）传感平台。首先将巯基化修饰的分子信标 1（MB1）固定在 Au 电极（GE）表面，然后目标 DNA 与 MB1 杂交，打开的 MB1 与带有二茂铁（Fc）标记的分子信标 2 组装，以置换目标 DNA，从而为下一轮 MB1-目标杂交做好准备。此外，Fc 被限制在 GE 表面附近，以实现有效的电子转移，从而产生电流信号。最终，每个目标链都经历了多个循环，导致大量 Fc 被限制在 GE 附近，这导致 Fc 的电流显著增加。观察到的信号增益足以实现 0.74 fM 的检测限，具有从 10(-15)到 10(-10)M 的宽线性动态范围，并具有高选择性区分错配 DNA 与完美匹配的目标 DNA。因此，由于该 E-DNA 传感器无需酶且操作简单，因此具有广泛的传感器应用。
