Triple-Helix Molecular Switch Electrochemical Ratiometric Biosensor for Ultrasensitive Detection of Nucleic Acids
Triple-Helix Molecular Switch Electrochemical Ratiometric Biosensor for Ultrasensitive Detection of Nucleic Acids
复制标题
用于超灵敏核酸检测的三螺旋分子开关电化学比例生物传感器
DOI：
10.1021/acs.analchem.7b01251
复制
发表时间：
2017-09-05
影响因子：
7.4
通讯作者：
Chen, Jinhua
中科院分区：
文献类型：
--
作者：
Xiong, Erhu;Li, Zhenzhen;Chen, Jinhua
生物分子受体，例如在结合到特定靶时在两种或更多种构象之间切换的核酸，可以用于构建特异性和灵敏的生物传感器。本文基于电化学双信号比率测量策略和三螺旋分子开关，研制了一种选择性、可重复使用、结构简单的电化学DNA（E-DNA）生物传感器，用于靶DNA（T-DNA）的检测。用亚甲蓝标记的发夹状DNA捕获探针（MB-DNA）通过Au-S键在金电极（GE）表面自组装，然后两端修饰两个二茂铁以增强氧化信号的单链DNA（Fc-DNA）与MB-DNA杂交形成三螺旋构象。当T-DNA存在时，Fc-DNA与T-DNA杂交，分解三螺旋茎并允许MB-DNA恢复到其发夹结构。因此，Fc标签扩散远离GE表面，而MB标签保持附着在其附近，导致Fc（I-Fc）的峰电流降低和MB（I-MB）的峰电流增加。I-MB/I-Fc值与T-DNA浓度在0.5 ~ 80 pM范围内呈线性关系，检测限低至0.12 pM。E-DNA生物传感器在多种分析物的电化学检测中具有巨大的潜力，并可作为早期临床诊断和生物医学研究的生物传感平台。
Biomolecular receptors such as nucleic acids that switch between two or more conformations upon binding to a specific target can be used to build specific and sensitive biosensors. In this work, based on the electrochemical dual signaling ratiometric strategy and triple-helix molecular switch, we developed a selective, reusable, and simple electrochemical DNA (E-DNA) biosensor for target DNA (T-DNA) detection. A hairpin DNA capture probe labeled with methylene blue (MB-DNA) self-assembles on the surface of a gold electrode (GE) through Au-S bond, and then a single-strand DNA modified with two ferrocenes (Fc-DNA) on each end to enhance the oxidation signal hybridizes with the MB-DNA to form a triple-helix conformation. When T-DNA exists, the Fc-DNA hybridizes with T-DNA disassembling the triple-helix stem and allowing the MB-DNA to revert to its hairpin structure. Hence, the Fc tags diffuse away from the GE surface while the MB tags remain affixed close to it, resulting in a decrease in the peak current of Fc (I-Fc) and an increase in that of MB (I-MB). The linear relationship between the value of I-MB/I-Fc and the T-DNA concentration is observed from 0.5 to 80 pM, and the limit of detection is as low as 0.12 pM. The developed E-DNA biosensor may have great potential in the electrochemical detection of a wide range of analytes and be a biosensing platform for early clinical diagnosis and biomedical research.