AbstractsThe authors describe a dual-signal electrochemical biosensor for highly sensitive determination of the HIV-1 related gene. This method is based on the application of cascaded toehold-mediated strand displacement reactions (TMSDRs) in combination with non-enzymatic target recycling amplification (TRA). A DNA machine with two TMSDRs was designed, and this resulted in reusable target and an output of two oligonucleotides, referred to as strand A (AS) labeled with the redox tag methylene blue (MB) and as untagged strand B (BS). A ferrocene (Fc)-modified signal probe (Fc-P1) is immobilized on the gold electrode surface by hybridizing with a thiolated probe (P2). The labeled AS causes the dissociation of Fc molecules and the gathering of MB molecules via strand displacement reaction. The target gene triggers TMSDRs and TRA. This leads to an increase in the distance changes between the redox tags and the gold electrode. The assay works in the 1 pM to 10 nM concentration range. On account of target recycling and dual recognition, the limit of detection is as low as 0.88 pM (at an S/N ratio of 3). The assay also has a remarkable selectivity which is ascribed to the use of both cascaded TMSDRs and dual recognition. In our perception, this assay represents a robust means of wide scope in that it may be applied to the detection of various kinds of nucleic acid even in complex samples. Graphical abstractSchematic of a dual-signal electrochemical biosensor based on cascaded toehold-mediated strand displacement and non-enzymatic target recycling amplification strategy for the HIV-1 related gene detection. Two electroactive molecules are used to produce electrochemical signals in this “signal-on/off” sensing system.

中文翻译：

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用于 HIV-1 相关基因电化学测定的级联脚趾介导的链置换以及非酶促靶标回收扩增

摘要作者描述了一种双信号电化学生物传感器，用于高度灵敏地测定 HIV-1 相关基因。该方法基于级联立足点介导的链置换反应 (TMSDR) 与非酶促目标再循环扩增 (TRA) 相结合的应用。设计了具有两个 TMSDR 的 DNA 机器，这导致了可重复使用的目标和两个寡核苷酸的输出，称为链 A (AS)，标记有氧化还原标签亚甲蓝 (MB)，未标记链 B (BS)。二茂铁 (Fc) 修饰的信号探针 (Fc-P1) 通过与硫醇化探针 (P2) 杂交固定在金电极表面。标记的AS通过链置换反应引起Fc分子的解离和MB分子的聚集。靶基因触发 TMSDRs 和 TRA。这导致氧化还原标签和金电极之间的距离变化增加。该测定在 1 pM 到 10 nM 的浓度范围内工作。由于目标回收和双重识别，检测限低至 0.88 pM（信噪比为 3）。该测定还具有显着的选择性，这归因于使用级联 TMSDR 和双重识别。在我们看来，该测定代表了一种范围广泛的稳健手段，因为它甚至可以应用于复杂样品中的各种核酸的检测。基于级联脚趾介导的链置换和非酶促靶标回收扩增策略的双信号电化学生物传感器示意图，用于 HIV-1 相关基因检测。