Department of Laboratory Medicine, Guizhou Provincial People's Hospital, Guiyang, 550002, China.
Department of Endocrinology, Chongqing Three Gorges Central Hospital, Chongqing, 404000, China.
Mikrochim Acta. 2019 Jul 10;186(8):522. doi: 10.1007/s00604-019-3615-2.
A nonenzymatic fluorometric assay is described for highly sensitive and selective detection of silver ion. It is making use of a controlled DNA assembly and an AND logic operation of a multiple-component DNAzyme (MNAzyme). It corresponds to an Ag(I)-responsive three-way junction (3-WJ) assembly. The tailored probes of the 3-WJ architecture were designed with complementary domains for subsequent assembly. Cytosine (C)-cytosine mismatches at one-way junction were set as the sensing element for Ag(I). Upon exposure to Ag(I) as an input, C-Ag(I)-C pairs are being formed. This enhances the binding energy between these separate probes and thus promotes the formation of a nanostructure that represents an AND logic assembly of MNAzyme with an amplified output signal. This results in an Ag(I)-induced increase in fluorescence which is measured best at excitation/emission maxima of 645/670 nm. The method displays high selectivity and sensitivity, has a 5 pM detection limit at 3σ and a dynamic range that extends from 10 pM to 100 nM. Graphical abstract Schematic presentation of a new fluorescence system for determining silver ion by making use of cytosine-Ag(I)-cytosine pair formation, precisely-controlled DNA assembly and "AND" logic operation of multiple components DNAzyme (MNAzyme).
一种非酶荧光测定法被描述用于高灵敏度和选择性检测银离子。它利用受控的 DNA 组装和多个组分 DNA 酶（MNAzyme）的“与”逻辑运算。它对应于 Ag（I）响应的三链结（3-WJ）组装。3-WJ 结构的定制探针设计有互补结构域，以便随后进行组装。单向结处的胞嘧啶（C）-胞嘧啶错配被设置为 Ag（I）的传感元件。暴露于 Ag（I）作为输入时，形成 C-Ag（I）-C 对。这增强了这些单独探针之间的结合能，从而促进了纳米结构的形成，该纳米结构代表了具有放大输出信号的 MNAzyme 的“与”逻辑组装。这导致 Ag（I）诱导的荧光增加，在 645/670nm 的激发/发射最大值处测量最佳。该方法具有高选择性和灵敏度，在 3σ 时检测限为 5 pM，动态范围从 10 pM 扩展到 100 nM。
