The rational design of DNA tracks is an effective pathway to guide the autonomous movement and high-efficiency recognition in DNA walkers, showing outstanding advantages for the cascade signal amplification of electrochemical biosensors. However, the uncontrolled distance between two adjacent tracks on the electrode could increase the risk of derailment and interruption of the reaction. Hence, a novel four-way balanced cruciform-shaped DNA track (C-DNT) was designed as a structured pathway to improve the effectiveness and stability of the reaction in DNA walkers. In this work, two kinds of cruciform-shaped DNA were interconnected as a robust structure that could avoid the invalid movement of the designed DNA walker on the electrode. When hairpin H2 was introduced onto the electrode, the strand displacement reaction (SDR) effectively triggered movements of the DNA walker along the cruciform-shaped track while leaving ferrocene (Fc) on the electrode, leading to a significant enhancement of the electrochemical signal. This design enabled the walker to move in an excellent organized and controllable manner, thus enhancing the reaction speed and walking efficiency. Compared to other walkers moving on random tracks, the reaction time of the C-DNT-based DNA walker could be reduced to 20 min. Lead ion (Pb) was used as a model target to evaluate the analytical performance of this biosensor, which exhibited a low detection limit of 0.033 pM along with a wide detection ranging from 0.1 pM to 500 nM. This strategy presented a novel concept for designing a high-performance DNA walker-based sensing platform for the detection of contaminants.

中文翻译：

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由有序十字形 DNA 轨迹引导的高效 DNA 步行器，用于铅离子的超灵敏和快速电化学检测

DNA轨迹的合理设计是引导DNA步行器自主运动和高效识别的有效途径，在电化学生物传感器的级联信号放大方面显示出突出的优势。然而，电极上两个相邻轨道之间不受控制的距离可能会增加脱轨和反应中断的风险。因此，设计了一种新型四路平衡十字形DNA轨道（C-DNT）作为结构化途径，以提高DNA步行器中反应的有效性和稳定性。在这项工作中，两种十字形DNA相互连接成一个坚固的结构，可以避免设计的DNA步行器在电极上的无效运动。当发夹 H2 被引入电极时，链置换反应 (SDR) 有效地触发 DNA 步行者沿着十字形轨道运动，同时在电极上留下二茂铁 (Fc)，导致电化学信号显着增强。这种设计使步行者的运动具有良好的组织性和可控性，从而提高了反应速度和步行效率。与其他在随机轨道上移动的步行器相比，基于 C-DNT 的 DNA 步行器的反应时间可缩短至 20 分钟。使用铅离子 (Pb) 作为模型目标来评估该生物传感器的分析性能，该生物传感器表现出 0.033 pM 的低检测限以及 0.1 pM 至 500 nM 的宽检测范围。该策略提出了一种新颖的概念，用于设计基于 DNA walker 的高性能传感平台来检测污染物。