School of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR 72701, USA.
Sensors (Basel). 2017 Aug 28;17(9):1973. doi: 10.3390/s17091973.
is one of the most dangerous foodborne pathogens and poses a significant threat to human health. The objective of this study was to develop a portable impedance immunosensing system for rapid and sensitive detection of . in poultry. The developed portable impedance immunosensing system consisted of a gold interdigitated array microelectrode (IDAM), a signal acquisitive interface and a laptop computer with LabVIEW software. The IDAM was first functionalized with 16-Mercaptohexadecanoic acid, and streptavidin was immobilized onto the electrode surface through covalent bonding. Then, biotin-labelled . -antibody was immobilized onto the IDAM surface. Samples were dropped on the surface of the IDAM and the . cells in the samples were captured by the antibody on the IDAM. This resulted in impedance changes that were measured and displayed with the LabVIEW software. An equivalent circuit of the immunosensor demonstrated that the largest change in impedance was due to the electron-transfer resistance. The equivalent circuit showed an increase of 35% for the electron-transfer resistance value compared to the negative control. The calibration result indicated that the portable impedance immunosensing system could be used to measure the standard impedance elements, and it had a maximum error of measurement of approximately 13%. For pure culture detection, the system had a linear relationship between the impedance change and the logarithmic value of . cells ranging from 76 to 7.6 × 10⁶ CFU (colony-forming unit) (50 μL). The immunosensor also had a correlation coefficient of 0.98, and a high specificity for detection of . cells with a limit of detection (LOD) of 10² CFU (50 μL). The detection time from the moment a sample was introduced to the display of the results was 1 h. To conclude, the portable impedance immunosensing system for detection of . achieved an LOD that is comparable with commercial electrochemical impedance instruments. The developed impedance immunosensor has advantages in portability, low cost, rapid detection and label-free features showing a great potential for in-field detection of foodborne pathogens.
是食源性致病菌中最危险的一种，对人类健康构成重大威胁。本研究旨在开发一种便携式阻抗免疫传感系统，用于快速灵敏地检测家禽中的 。所开发的便携式阻抗免疫传感系统由金叉指微电极（IDAM）、信号采集接口和带有 LabVIEW 软件的笔记本电脑组成。IDAM 首先用 16-巯基十六烷酸功能化，然后通过共价键将链霉亲和素固定在电极表面。接着，将生物素标记的 -抗体固定在 IDAM 表面。将样品滴加到 IDAM 表面，样品中的 细胞被 IDAM 上的抗体捕获。这导致阻抗发生变化，并用 LabVIEW 软件进行测量和显示。免疫传感器的等效电路表明，阻抗的最大变化是由于电子转移电阻引起的。等效电路显示，与阴性对照相比，电子转移电阻值增加了 35%。校准结果表明，该便携式阻抗免疫传感系统可用于测量标准阻抗元件，其测量最大误差约为 13%。对于纯培养物检测，该系统的阻抗变化与 对数呈线性关系，范围从 76 到 7.6×10⁶ CFU（菌落形成单位）（50 μL）。免疫传感器的相关系数为 0.98，对 细胞的检测具有很高的特异性，检测限（LOD）为 10² CFU（50 μL）。从引入样品到显示结果的检测时间为 1 小时。总之，用于检测 的便携式阻抗免疫传感系统达到了与商用电化学阻抗仪器相当的 LOD。所开发的阻抗免疫传感器具有便携性、低成本、快速检测和无标记的优点，在食源性致病菌的现场检测中具有很大的应用潜力。
