Zhang Zhang, Zhang Li, Wang Youqiang, Yao Juan, Wang Ting, Weng Zhi, Yang Liu, Xie Guoming
Key Laboratory of Laboratory Medical Diagnostics of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, PR China; Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Luzhou, PR China.
Key Laboratory of Laboratory Medical Diagnostics of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing, PR China.
Anal Chim Acta. 2021 Feb 22;1147:108-115. doi: 10.1016/j.aca.2020.12.057. Epub 2020 Dec 30.
In this study, an ultrasensitive electrochemical miRNA biosensor based on toehold mediated strand displacement reaction circuits (SDRCs) and molecular beacon mediated isothermal circular strand displacement polymerization reaction (ICSDPR) has been proposed. During the SDRCs module, the cascade strand displacement reaction induces the recycling of the target let 7a and generation of a large amount of strand A (SA). The SA recognition opens the hairpin capture probe immobilized on the gold electrode, thus, varying the distance between the redox molecules and electrode surface. The primer mediated ICSDPR is observed to further generate a large amount of SA, thus, leading to a reduction in the signal. Considering these merits, the proposed method is observed to exhibit a log-linear linearity from 10 aM to 100 pM and ultrahigh sensitivity towards let 7a down to 6.2 aM, with a capability of distinguishing the let 7a family members, thereby, providing a new electrochemical route for early cancer screening.
在本研究中，提出了一种基于托脚介导的链置换反应电路（SDRCs）和分子信标介导的等温环状链置换聚合反应（ICSDPR）的超灵敏电化学miRNA生物传感器。在SDRCs模块中，级联链置换反应诱导靶标let 7a的循环利用并产生大量链A（SA）。SA识别打开固定在金电极上的发夹捕获探针，从而改变氧化还原分子与电极表面之间的距离。观察到引物介导的ICSDPR进一步产生大量SA，从而导致信号降低。考虑到这些优点，所提出的方法在10 aM至100 pM范围内呈现对数线性，对let 7a的超灵敏检测低至6.2 aM，具有区分let 7a家族成员的能力，从而为早期癌症筛查提供了一条新的电化学途径。
