Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
School of Public Health and Management, Chongqing Medical University, Chongqing 400016, China.
Anal Chem. 2020 Dec 1;92(23):15624-15631. doi: 10.1021/acs.analchem.0c03893. Epub 2020 Nov 10.
Herein, highly efficient deoxyribonucleic acid (DNA) walking on electrode surfaces was realized by regulating DNA tracks, which was applied to construct an ultrasensitive electrochemiluminescent (ECL) biosensor for BCR/ABL fusion gene detection. The well-regulated DNA tracks were constructed supersandwich hybridization chain reaction of two DNA strands (L and L) to generate periodic linear dsDNA concatemers, where an exposed L domain closed with blocking strands (BS). The prepared DNA tracks were further assembled onto the surface of the Au nanoparticle-functionalized g-CN nanohybrid (Au@g-CN NHs)-modified electrode, achieving well-regulated interfacial tracks for the DNA walker. On this state, folic acid-labeled BS (FA-BS) were close to Au@g-CN NHs, performing a quenched ECL emission. With existence of the BCR/ABL fusion gene, the target combined two walking DNA strands (WD and WD) to form the bipedal DNA walkers, which walked on the well-regulated interfacial DNA tracks and replaced the FA-BS to light up the ECL emission, realizing DNA walker-based signal amplification. Compared to randomly constructed DNA tracks, the well-regulated DNA tracks reduced the kinetics barrier and fitted the step size of the DNA walker, thus promoting the DNA walking efficiency and decreasing the risk of interruption in the walking process. As a result, the designed DNA walker presented higher efficiency and capacity in signal amplification. Benefiting from this efficient DNA walker strategy, the ECL biosensor achieved sensitive detection of the BCR/ABL fusion gene with a detection limit of 0.18 fM. This smart strategy proposed a brief strategy to promote the working efficiency of the biosensor, which presented great application potential in clinical molecular diagnosis.
在此，通过调控 DNA 轨迹，实现了高效的脱氧核糖核酸（DNA）在电极表面上的“行走”，并将其应用于构建用于 BCR/ABL 融合基因检测的超灵敏电化学发光（ECL）生物传感器。通过两条 DNA 链（L 和 L）的超三明治杂交链反应构建了规则的 DNA 轨迹，以生成周期性的线性 dsDNA 串联体，其中暴露的 L 结构域与封闭链（BS）闭合。制备的 DNA 轨迹进一步组装到功能化金纳米粒子的 g-CN 纳米杂化物（Au@g-CN NHs）修饰电极的表面上，实现了 DNA 行走器的规则界面轨迹。在这种状态下，叶酸标记的 BS（FA-BS）靠近 Au@g-CN NHs，表现出淬灭的 ECL 发射。存在 BCR/ABL 融合基因时，靶标结合两条行走 DNA 链（WD 和 WD）形成双足 DNA 行走器，在规则的界面 DNA 轨迹上行走，并取代 FA-BS 以点亮 ECL 发射，实现基于 DNA 行走器的信号放大。与随机构建的 DNA 轨迹相比，规则化的 DNA 轨迹降低了动力学障碍，适应了 DNA 行走器的步长，从而提高了 DNA 行走效率并降低了行走过程中断的风险。因此，所设计的 DNA 行走器在信号放大方面表现出更高的效率和能力。受益于这种高效的 DNA 行走器策略，ECL 生物传感器实现了对 BCR/ABL 融合基因的灵敏检测，检测限为 0.18 fM。该智能策略提出了一种提高生物传感器工作效率的简单策略，在临床分子诊断中具有巨大的应用潜力。
