Division of Materials Science, Faculty of Advanced Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo, Kumamoto, 860-8555, Japan.
Anal Sci. 2020 Aug 10;36(8):959-964. doi: 10.2116/analsci.19P456. Epub 2020 Feb 14.
Ferrocene (Fc) and β-cyclodextrin (βCyD) were modified at each end of stem-loop structured DNA as an electrochemical signal generator and its quencher, respectively, to give an electrochemical molecular beacon (eMB). A relatively high efficiency of signal quenching was achieved by an inclusion complex (βCyD ⊃ Fc) formation that was induced on the stem structure of the closed form (= stem-loop structure) of eMB. With the addition of target DNA, the structure of eMB opened to form a linear duplex, where the Fc dissociated from the βCyD to restore its intrinsic electrochemical signal. The signal contrast of the electric current for this off/on-type sensor was high, ca. 95. This technique did not require any modification of the electrode surface, and it realized the detection of the target nucleic acids in a homogeneous solution with a high sensitivity using high-performance liquid chromatography (HPLC) equipped with electrochemical detector.
二茂铁（Fc）和β-环糊精（βCyD）分别修饰在发夹结构 DNA 的两端，作为电化学信号发生器和猝灭剂，得到电化学分子信标（eMB）。通过在 eMB 的闭环（=发夹结构）的茎结构上诱导形成包含配合物（βCyD⊃Fc），实现了相对高效率的信号猝灭。随着靶 DNA 的加入，eMB 的结构打开形成线性双链体，其中 Fc 从 βCyD 中解离出来，恢复其内在的电化学信号。这种开/关型传感器的电流信号对比度高，约为 95。该技术不需要对电极表面进行任何修饰，并且使用配备电化学检测器的高效液相色谱（HPLC）在均相溶液中实现了对靶核酸的高灵敏度检测。
