College of Chemistry and Chemical Engineering, Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong, Sichuan 637000, China.
Anal Chem. 2023 May 2;95(17):7006-7013. doi: 10.1021/acs.analchem.3c00546. Epub 2023 Apr 21.
Herein, an electrochemiluminescence (ECL) and electrochemical (EC) dual-mode biosensor platform with a self-powered DNAzyme walking machine was established for accurate and sensitive detection of miRNA-21. By employing a magnesium ion (Mn)-dependent DNAzyme cleavage cycling reaction, the walking machine was built by assembling DNAzyme walking strands and ferrocene (Fc)-labeled substrate strands on the Au nanoparticles and graphitic carbon nitride nanosheet (g-CN NS)-covered electrode. The DNAzyme walking strand was first prohibited by a blocker strand. After the addition of target miRNA-21 and Mn, the DNAzyme walker could be activated and produce autonomous movements along the electrode track fueled by Mn-dependent DNAzyme-catalyzed substrate cleavage without additional energy supply. Notably, each walking step resulted in the cleavage of a substrate strand and the release of a Fc-labeled DNA strand fragment, allowing us to acquire an extreme ECL signal recovery of g-CN inhibited by Fc. Meanwhile, numerous Fc-labeled DNA fragments escaped from the surface of the electrode, directly producing an obvious decrease in the square wave voltammetry (SWV) signal from Fc on the same sensing platform. This work not only avoided difficultly assembling various signal indicators but also significantly improved the sensitivity through using self-powered DNAzyme-walker amplification. Moreover, the proposed design employed the same reaction to produce two signal output modes, which could eliminate the interference from diverse reactive pathways on the outcome to mutually improve the accuracy. Therefore, the dual-mode miRNA-21 biosensor exhibited wide detection ranges of 100 aM to 100 nM with low detection limits of 54.3 and 78.6 aM by ECL and SWV modes, respectively, which provided an efficient and universal biosensing approach with extensive applications in early disease diagnosis and bioanalysis.
在此，建立了一种基于电致化学发光（ECL）和电化学（EC）双模的生物传感器平台，该平台带有自供电 DNA zyme 行走机器，用于准确灵敏地检测 miRNA-21。通过利用镁离子（Mn）依赖的 DNAzyme 切割循环反应，将 DNAzyme 行走链和二茂铁（Fc）标记的底物链组装在金纳米粒子和石墨相氮化碳纳米片（g-CN NS）覆盖的电极上，构建了行走机器。首先，将 DNAzyme 行走链被阻断链所抑制。加入靶标 miRNA-21 和 Mn 后，DNAzyme 行走器可以被激活，并在 Mn 依赖的 DNAzyme 催化的底物切割的驱动下，在电极轨道上自主运动，而无需额外的能量供应。值得注意的是，每个行走步骤都会导致一个底物链的切割和一个 Fc 标记的 DNA 链片段的释放，这使得我们能够获得由 Fc 抑制的 g-CN 的极端 ECL 信号恢复。同时，大量的 Fc 标记的 DNA 片段从电极表面逃脱，直接导致同一传感平台上 Fc 的方波伏安法（SWV）信号明显下降。这项工作不仅避免了难以组装各种信号指示剂的问题，而且通过使用自供电 DNAzyme 行走器放大，显著提高了灵敏度。此外，所提出的设计采用相同的反应产生两种信号输出模式，可以消除不同反应途径对结果的干扰，从而相互提高准确性。因此，这种双模 miRNA-21 生物传感器通过 ECL 和 SWV 模式分别具有 100 aM 至 100 nM 的宽检测范围和 54.3 和 78.6 aM 的低检测限，为早期疾病诊断和生物分析提供了一种高效通用的生物传感方法。
