Background

Aptamers, consisting of specialized single-stranded nucleic acids, are engineered through the SELEX technique to recognize specific targets with strong affinity. Aptamers are exceptionally useful in various sensor technologies, such as fluorescence-based sensors, electrochemical sensors, and colorimetric detection systems. Due to its high sensitivity, specificity and fast response, electrochemical aptasensor shows great application prospects in analytical detection, food safety, and environmental monitoring. However, one aptasensor can usually detect only one type of target, limiting its universality in practical applications.

Results

Here, we constructed a dual-switch and label-free electrochemical aptasensor based on split aptamer and nuclease. The feasibility, specificity, and sensitivity of the aptasensor were investigated by using thrombin and adenosine triphosphate (ATP) as targets. Split aptamer can not only capture target specifically but also form a stable sandwich structure with the target. In the presence of thrombin, it triggered a hydrolysis reaction of exonuclease I, leading to a decrease in the impedance signal. Differently, the presence of ATP could form a sandwich structure with split aptamers, leading to an increase in output signals. The aptasensor achieved sensitive and specific detection of thrombin and ATP, with low detection limits of 0.76 pM and 0.27 pM, respectively.

Significance and Novelty

The aptasensor realized the detection of two targets without replacing any reagents or equipment, which greatly saved time and cost. Furthermore, electrochemical impedance spectroscopy (EIS) uses impedance as an output signal, showing great application prospects in electrochemical aptasensors as label-free and simple methods. Because of its simplicity, label-free, and sensitivity in complex samples, the split aptamer-assisted aptasensor provides new ideas and methods in early diagnosis of diseases.

中文翻译：

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一种基于分离适配体的双开关电化学适配体，用于凝血酶和 ATP 的无标记检测

 背景

适配子由专门的单链核酸组成，通过 SELEX 技术进行工程改造，以强亲和力识别特定靶标。适配子在各种传感器技术中特别有用，例如基于荧光的传感器、电化学传感器和比色检测系统。由于其高灵敏度、特异性和快速响应性，电化学适配传感器在分析检测、食品安全和环境监测方面显示出巨大的应用前景。然而，一个 aptasensor 通常只能检测到一种类型的目标，这限制了它在实际应用中的通用性。

 结果

在这里，我们构建了一个基于分裂适配体和核酸酶的双开关和无标记电化学适配体传感器。以凝血酶和三磷酸腺苷 （ATP） 为靶点，研究适配体传感器的可行性、特异性和敏感性。分裂适配体不仅可以特异性捕获目标，还可以与目标形成稳定的夹心结构。在凝血酶存在下，它触发了核酸外切酶 I 的水解反应，导致阻抗信号降低。不同的是，ATP 的存在可以形成带有分裂适配体的夹心结构，从而导致输出信号的增加。aptasensor 实现了对凝血酶和 ATP 的灵敏和特异性检测，检出限分别为 0.76 pM 和 0.27 pM。

 意义和新颖性

aptasensor 实现了对两个目标的检测，无需更换任何试剂或设备，大大节省了时间和成本。此外，电化学阻抗谱 （EIS） 使用阻抗作为输出信号，作为无标记和简单的方法在电化学适配体传感器中显示出巨大的应用前景。由于其简单、无标记和对复杂样品的敏感性，分离适配体辅助适配体传感器为疾病的早期诊断提供了新的思路和方法。