Department of Food Science and Technology, Faculty of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
Research Institute of Biotechnology and Bioengineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
Mikrochim Acta. 2018 Nov 9;185(12):538. doi: 10.1007/s00604-018-3075-0.
This work describes an aptasensor for the foodborne pathogen Shigella dysenteriae (S. dysenteriae). A glassy carbon electrode (GCE) was modified with gold nanoparticles (AuNPs) by electrodeposition. Then, thiolated aptamer for S. dysenteriae detection was self-assembled on the surface of the modified GCE, and any free residual AuNPs were blocked with 6-mercapto-1-hexanol. The size, morphology, and distribution of the AuNPs were characterized by field emission scanning electron microscopy. Detection of S. dysenteriae was performed measurement of the charge transfer resistance (R) before and after addition of S. dysenteriae using hexacyanoferrate as an electrochemical probe. The interaction between the aptamer and outer-membrane proteins of S. dysenteriae lead to an increase in the R of the sensor. The assay has a linear dynamic range that extends from 10 to 10 CFU.mL and a limit of detection of 10 CFU.mL. It can differentiate between alive S. dysenteriae and other pathogens. Dead S. dysenteriae cells do not have any effect on selectivity. Unpasteurized and pasteurized skim milk and some water samples were spiked with S. dysenteriae and then successfully examined by this method. The results were validated by real-time PCR. The method is fast, low-cost, highly sensitive, and specific. Hence, it represents a valuable tool in food quality control. Graphical abstract Schematic presentation of a label free impedimetric aptasensor for Shigella dysenteriae using a glassy carbon electrode modified with gold nanoparticles (AuNPs) and 6-mercapto-1-hexanol (MCH). The limit of detection of this aptasensor is as low as 1 CFU.mL for target bacteria.
本文描述了一种用于检测食源性致病菌志贺氏痢疾杆菌（S. dysenteriae）的适体传感器。通过电沉积将金纳米粒子（AuNPs）修饰到玻碳电极（GCE）上。然后，将用于检测 S. dysenteriae 的硫醇化适体自组装到修饰后的 GCE 表面，并用 6-巯基-1-己醇封闭任何游离的 AuNPs。通过场发射扫描电子显微镜对 AuNPs 的尺寸、形态和分布进行了表征。使用亚铁氰化钾作为电化学探针，通过测量添加 S. dysenteriae 前后的电荷转移电阻（R）来检测 S. dysenteriae。适体与 S. dysenteriae 外膜蛋白的相互作用导致传感器的 R 增加。该测定法具有从 10 到 10^CFU.mL 的线性动态范围和 10^CFU.mL 的检测限。它可以区分活的 S. dysenteriae 和其他病原体。死的 S. dysenteriae 细胞对选择性没有任何影响。未经巴氏消毒和巴氏消毒的脱脂牛奶和一些水样中添加了 S. dysenteriae，然后用该方法成功进行了检测。结果通过实时 PCR 进行了验证。该方法快速、低成本、高灵敏度且具有特异性。因此，它代表了食品质量控制的有价值工具。 图表摘要 利用玻碳电极修饰的金纳米粒子（AuNPs）和 6-巯基-1-己醇（MCH）构建用于志贺氏痢疾杆菌（S. dysenteriae）的无标记阻抗适体传感器的示意图。该适体传感器的检测限低至 1 CFU.mL 用于目标细菌。
