Electrochemical interrogation of conformational changes as a reagentless method for the sequence-specific detection of DNA
Electrochemical interrogation of conformational changes as a reagentless method for the sequence-specific detection of DNA
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DOI：
10.1073/pnas.1633515100
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发表时间：
2003-08-05
影响因子：
11.1
通讯作者：
Heeger, AJ
中科院分区：
文献类型：
--
作者：
Fan, CH;Plaxco, KW;Heeger, AJ
我们报告了一种通过类似于光分子信标方法的构象变化将DNA杂交转化为易于检测的电化学信号的无试剂转导策略。该策略涉及一种电活性，二茂铁标记的DNA茎环结构，该结构通过简单的金硫醇化学自组装到金电极上。杂交在这种表面受限的DNA结构中引起了很大的构象变化，这反过来又显著地改变了电极和可还原标签之间的电子转移隧道距离。在目标DNA浓度低至10pm时，通过循环伏安法可以很容易地测量电子传递效率的变化。与现有的光学方法相比，基于该策略的电化学DNA （E-DNA）传感器可以检测目标DNA的飞摩尔，而无需使用笨重且昂贵的光学元件、光源或光电探测器。与之前报道的电化学方法相比，E-DNA传感器在不使用外源试剂的情况下实现了这种令人印象深刻的灵敏度，并且不牺牲选择性或可重用性。因此，E-DNA传感器提供了方便，可重复使用的检测皮摩尔DNA的承诺。
We report a strategy for the reagentless transduction of DNA hybridization into a readily detectable electrochemical signal by means of a conformational change analogous to the optical molecular beacon approach. The strategy involves an electroactive, ferrocene-tagged DNA stem-loop structure that self-assembles onto a gold electrode by means of facile gold-thiol chemistry. Hybridization induces a large conformational change in this surface-confined DNA structure, which in turn significantly alters the electron-transfer tunneling distance between the electrode and the redoxable label. The resulting change in electron transfer efficiency is readily measured by cyclic voltammetry at target DNA concentrations as low as 10 pM. In contrast to existing optical approaches, an electrochemical DNA (E-DNA) sensor built on this strategy can detect femtomoles of target DNA without employing cumbersome and expensive optics, light sources, or photodetectors. In contrast to previously reported electrochemical approaches, the E-DNA sensor achieves this impressive sensitivity without the use of exogenous reagents and without sacrificing selectivity or reusability. The E-DNA sensor thus offers the promise of convenient, reusable detection of picomolar DNA.