Microchimica Acta ( IF 5.3 ) Pub Date : 2021-09-26 , DOI: 10.1007/s00604-021-04962-3 Yina Sun 1 , Chuan Huang 1 , Qian Wang 1, 2 , Shenguang Ge 1 , Xiujin Sun 3 , Peini Zhao 2 , Jinghua Yu 2
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Based on the prominent electrochemiluminescence (ECL) performances of molybdenum disulfide-graphene quantum dots (MoS2-GQDs) nanocomposite and combined with enzyme-assisted recycling DNA walker signal amplification, an “on-off” switch ECL biosensor was proposed for sensitive assay of specific DNA sequences. Noticeably, MoS2 with two-dimensional nanosheet structure increased the loading capacity of GQDs to support abundant hairpin DNA (H). The composites of MoS2 and GQDs facilitated the charge transfer in ECL process, which significantly improved the ECL signal to achieve an “on” state. Then, the DNA walker cyclic amplification was performed by adding the target DNA and exonuclease III (Exo III). Finally, the DNA2-Fc-DNA1 was introduced into the system as ECL signal quencher, turning the ECL signal into an “off” state. The sensitive assay of ultra-low concentration specific DNA sequences was realized according to the variation of ECL signal strength before and after the existence of target DNA. The proposed ECL biosensor showed a good linear relationship ranging from 1 nM to 100 aM with a detection limit of 25.1 aM, providing a powerful strategy for biomedical research and clinical analysis.
Graphical abstract
中文翻译：
基于二硫化钼-石墨烯量子点纳米复合材料和DNA walker信号放大的电化学发光生物传感器用于DNA检测
基于二硫化钼-石墨烯量子点（MoS 2 -GQDs）纳米复合材料突出的电化学发光（ECL）性能，并结合酶辅助回收 DNA walker 信号放大，提出了一种“开-关”开关 ECL 生物传感器，用于灵敏测定特定的 DNA 序列。值得注意的是，具有二维纳米片结构的MoS 2增加了 GQDs 的负载能力，以支持丰富的发夹 DNA (H)。MoS 2的复合材料和 GQDs 促进了 ECL 过程中的电荷转移，这显着改善了 ECL 信号以实现“开”状态。然后，通过添加目标DNA和核酸外切酶III（Exo III）进行DNA walker循环扩增。最后，将 DNA2-Fc-DNA1 作为 ECL 信号猝灭剂引入系统，将 ECL 信号变为“关闭”状态。根据靶DNA存在前后ECL信号强度的变化，实现超低浓度特异性DNA序列的灵敏检测。所提出的 ECL 生物传感器在 1 nM 至 100 aM 范围内显示出良好的线性关系，检测限为 25.1 aM，为生物医学研究和临床分析提供了强有力的策略。
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