Key Laboratory of Optic-Electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao, Shandong, 266042, China.
Key Laboratory of Optic-Electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao, Shandong, 266042, China.
Biosens Bioelectron. 2021 Jan 1;171:112706. doi: 10.1016/j.bios.2020.112706. Epub 2020 Oct 7.
In this work, a self-propelled DNA machine was proposed for enzyme-free and ultrasensitive electrochemical detection of nucleic acid, which was based on a new strategy of the fuel strand-powered target recycling and successive proximity-based inter-strand displacement for distinct signal amplification. A three-strand duplex DNA (TSD) probe was immobilized onto electrode for target DNA recognition via a fuel strand-powered strand displacement circuit, accompanied with the target recycling and the association of fuel strand onto electrode for signal amplification and readout. The associated fuel strand contained a protruding tail sequence that could be used as a target analogy to activate the neighboring TSD probe based on the proximity-based inter-strand displacement effect, inducing the self-propelled association of fuel strand onto electrode for further signal amplification. The detection performance (dynamic response range, linear interval and detection limit) of current electrochemical DNA machine could be interestingly tuned by changing the tail sequence length of fuel strand, showing the potential for different analysis requirements. The lowest detection limit of 0.1 fM could be achieved, which was lower about two orders of magnitude than that by the typical fuel strand-powered target recycling strategy. Therefore, the developed sensing system exhibits a new, simple and powerful means for amplified detection of nucleic acid and may hold great potentials in bioanalysis, disease diagnosis and biomedicine.
在这项工作中，提出了一种自主推进的 DNA 机器，用于无酶和超灵敏的电化学检测核酸，这是基于一种新的策略，即燃料链驱动的目标回收和连续的基于邻近的链间置换，以实现明显的信号放大。三链双链 DNA（TSD）探针被固定在电极上，通过燃料链驱动的链置换电路识别靶 DNA，同时伴随着目标回收和燃料链与电极的结合，用于信号放大和读出。相关的燃料链包含一个突出的尾巴序列，可作为目标类似物被激活，基于基于邻近的链间置换效应的邻近 TSD 探针，诱导燃料链自主地与电极结合，用于进一步的信号放大。电流电化学 DNA 机器的检测性能（动态响应范围、线性区间和检测限）可以通过改变燃料链的尾巴序列长度来有趣地调节，显示出满足不同分析要求的潜力。可以实现低至 0.1 fM 的最低检测限，比典型的燃料链驱动的目标回收策略低约两个数量级。因此，所开发的传感系统为核酸的放大检测展示了一种新的、简单而强大的手段，可能在生物分析、疾病诊断和生物医学领域具有巨大的潜力。
