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An electrochemical aptasensor based on cocoon-like DNA nanostructure signal amplification for the detection of Escherichia coli O157:H7.
Analyst ( IF 3.6 ) Pub Date : 2020-08-19 , DOI: 10.1039/d0an01258k
Huasong Bai 1 , Shengjun Bu , Wensen Liu , Chengyu Wang , Zhongyi Li , Zhuo Hao , Jiayu Wan , Ye Han
Affiliation  

We developed an electrochemical aptasensor based on cocoon-like DNA nanostructures as signal tags for highly sensitive and selective detection of Escherichia coli O157:H7. The stable cocoon-like DNA nanostructures synthesized by the rolling circle amplification reaction were loaded with hemin as electrochemical signal tags to amplify the signals. The single-stranded DNA capture probes were modified on the surface of a Au electrode via a Au–S bond. The E. coli O157:H7 specific aptamer and capture probe formed double-stranded DNA structures on the Au electrode. The aptamer preferentially bound to E. coli O157:H7, causing the dissociation of some aptamer-capture probes and releasing some capture probes. Subsequently, the free capture probes hybridized with the DNA nanostructures through the cDNA sequence. Under optimal conditions, the change in the electrochemical signal was proportional to the logarithm of E. coli O157:H7 concentration, from 10 to 106 CFU mL−1, and the detection limit was estimated to be 10 CFU mL−1. The electrochemical aptasensor could be readily used to detect various pathogenic bacteria and to provide a new method of early diagnosis of pathogenic microorganisms.

中文翻译:

基于茧状DNA纳米结构信号放大的电化学适体传感器,用于检测大肠杆菌O157:H7。

我们开发了基于茧状DNA纳米结构作为信号标签的电化学适体传感器,用于高灵敏度和选择性检测大肠杆菌O157:H7。通过滚环扩增反应合成的稳定的茧状DNA纳米结构被加载有血红素作为电化学信号标签,以放大信号。单链DNA捕获探针通过Au-S键在Au电极的表面进行了修饰。的大肠杆菌O157:H7的特定适体和捕获探针形成的双链DNA结构上Au电极。适体优先结合大肠杆菌O157:H7,导致一些适体捕获探针解离并释放一些捕获探针。随后,游离捕获探针通过cDNA序列与DNA纳米结构杂交。在最佳条件下,电化学信号的变化与大肠杆菌O157:H7浓度的对数成正比,从10到10 6 CFU mL -1,检测极限估计为10 CFU mL -1。电化学适体传感器可以很容易地用于检测各种病原细菌,并提供一种早期诊断病原微生物的新方法。
更新日期:2020-09-15
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