Ultraspecific electrochemical DNA biosensor by coupling spontaneous cascade DNA branch migration and dual-signaling sensing strategy.
Ultraspecific electrochemical DNA biosensor by coupling spontaneous cascade DNA branch migration and dual-signaling sensing strategy.
复制标题
DOI：
10.1016/j.bios.2015.11.071
复制
发表时间：
2016-04
影响因子：
12.6
通讯作者：
Ting Wang;Lili Zhou;Shulian Bai;Zhang Zhang-Zhang;Junlong Li;Xiaoying Jing;G. Xie
中科院分区：
文献类型：
--
作者：
Ting Wang;Lili Zhou;Shulian Bai;Zhang Zhang-Zhang;Junlong Li;Xiaoying Jing;G. Xie
利用自发级联DNA分支迁移和双信号传感策略，我们开发了一种新型的通用电化学生物传感器，用于高特异性和高灵敏度的核酸检测。靶链（Ts）与二茂铁（Fc）标记的信号探针（Fc- s1）竞争性杂交，该探针在链位移后被保护链（Ps）阻断，形成Ts/Fc- s1双链。通过与巯基化捕获探针（Cp）杂交，将亚甲基蓝修饰的信号探针（MB- s2）固定在Au电极表面。然后，得到的反应物（Ts/Fc-S1和MB-S2/Cp）发生自发的DNA分支迁移，产生两种杂交产物（Fc-S1/Cp和MB-S2/Ts）。这些反应导致MB分子的解离和Fc分子的聚集。该DNA生物传感器的检测机制涉及氧化还原标签与Au电极之间的距离变化，这与靶诱导的级联DNA分支迁移有关。此外，我们合理设计了级联DNA分支迁移在ΔG°≈0时自发发生，在此条件下，碱基错配引起的微小热力学变化对杂交产率的影响不成比例地大。这种“信号开/关”传感系统显示出卓越的分析性能和超高的识别能力，甚至对单碱基不匹配。碱基突变或改变的最大判别因子（DF）可达17.9。因此，我们的电化学生物传感器在生物医学研究和早期临床诊断方面具有很大的应用潜力。
Using spontaneous cascade DNA branch migration and dual-signaling sensing strategy, we developed a novel universal electrochemical biosensor for the highly specific and sensitive detection of nucleic acids. A target strand (Ts) competitively hybridized with a ferrocene (Fc)-labeled signal probe (Fc-S1), which was blocked by a protector strand (Ps), after strand displacement to form the Ts/Fc-S1 duplex. A methylene blue (MB)-modified signal probe (MB-S2) was immobilized on the Au electrode surface by hybridizing with a thiolated capture probe (Cp). Then, the obtained reactants (Ts/Fc-S1 and MB-S2/Cp) suffered spontaneous DNA branch migration and produced two hybridization products (Fc-S1/Cp and MB-S2/Ts). These reactions led to the dissociation of MB molecules and the collection of Fc molecules. The detection mechanism of this DNA biosensor involved distance variation between the redox tags and the Au electrode, which was associated with target-induced cascade DNA branch migration. Moreover, we rationally designed the cascade DNA branch migration to occur spontaneously with ΔG°≈0, at which slight thermodynamic changes caused by base mismatch exerted a disproportionately large effect on the hybridization yield. This “signal-on/off” sensing system exhibited a remarkable analytical performance and an ultrahigh discrimination capability even against a single-base mismatch. The maximum discrimination factor (DF) of base mutations or alterations can reach 17.9. Therefore, our electrochemical biosensor might hold a great potential for further applications in biomedical research and early clinical diagnosis.