College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, China.
Anal Bioanal Chem. 2021 Mar;413(8):2071-2079. doi: 10.1007/s00216-020-03141-2. Epub 2021 Feb 19.
A simple fluorescence detection platform has been established for acetamiprid assay based on DNA three-way junctions (TWJs), which can triple the fluorescence signal without any other amplification. It is designed with three single-stranded DNAs (ssDNA), each of which contains one-third or two-thirds of the G-quadruplex sequence at each end. Upon the addition of acetamiprid, the conformation of the aptamer-containing double-stranded DNA (dsDNA) changes from its original conformation and releases a strand of ssDNA. This ssDNA, with the other two ssDNAs, can assemble into DNA TWJs, and the three pairs of the branched ends of the DNA TWJs are adjacent to each other, allowing them to form three units of G-quadruplexes. Hence, the fluorescence of N-methyl mesoporphyrin IX (NMM) is lighted by the nascent G-quadruplexes. Graphene oxide (GO) is then added to minimize the detection background by absorbing the free NMM and non-target-induced ssDNA. The proposed strategy can assay acetamiprid in a wide linear range of 0-500 nM with a detection limit of 5.73 nM. More importantly, this assay platform demonstrates high potential for acetamiprid assay in food control and environmental monitoring.
建立了一种基于 DNA 三链结构（TWJ）的用于测定涕灭威的简单荧光检测平台，该平台无需任何其他放大即可将荧光信号增强三倍。它由 3 条单链 DNA（ssDNA）组成，每条 ssDNA 的两端都包含三分之一或三分之二的 G-四链体序列。加入涕灭威后，含适体的双链 DNA（dsDNA）的构象从其原始构象发生变化并释放一条 ssDNA。该 ssDNA 与另外两条 ssDNA 一起组装成 DNA TWJ，并且 DNA TWJ 的三个分支末端彼此相邻，允许它们形成三个 G-四链体单元。因此，新生的 G-四链体点亮了 N-甲基甲川卟啉 IX（NMM）的荧光。然后加入氧化石墨烯（GO），通过吸收游离的 NMM 和非靶标诱导的 ssDNA 来最小化检测背景。该策略可以在 0-500 nM 的宽线性范围内测定涕灭威，检测限为 5.73 nM。更重要的是，该检测平台在食品控制和环境监测中具有测定涕灭威的巨大潜力。
