期刊论文详细信息
Biosensors
A Label-Free Impedance Immunosensor Using Screen-Printed Interdigitated Electrodes and Magnetic Nanobeads for the Detection of E. coli O157:H7
Ronghui Wang1  Jacob Lum5  Zach Callaway1  Jianhan Lin3  Walter Bottje2  Yanbin Li1  Nicole Jaffrezic-Renault4 
[1] Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR 72701, USA; E-Mails:;Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA; E-Mail:;College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China; E-Mail:Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR 72701, USA;;Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA; E-Mail:
关键词: immunosensor;    magnetic nanobeads;    impedance;    screen-printed interdigitated electrode;    E. coli O157:H7;    rapid detection;   
DOI  :  10.3390/bios5040791
来源: mdpi
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【 摘 要 】

Escherichia coli O157:H7 is one of the leading bacterial pathogens causing foodborne illness. In this study, an impedance immunosensor based on the use of magnetic nanobeads and screen-printed interdigitated electrodes was developed for the rapid detection of E. coli O157:H7. Magnetic nanobeads coated with anti-E. coli antibody were mixed with an E. coli sample and used to isolate and concentrate the bacterial cells. The sample was suspended in redox probe solution and placed onto a screen-printed interdigitated electrode. A magnetic field was applied to concentrate the cells on the surface of the electrode and the impedance was measured. The impedance immunosensor could detect E. coli O157:H7 at a concentration of 104.45 cfu·mL−1 (~1400 bacterial cells in the applied volume of 25 μL) in less than 1 h without pre-enrichment. A linear relationship between bacteria concentration and impedance value was obtained between 104 cfu·mL−1 and 107 cfu·mL−1. Though impedance measurement was carried out in the presence of a redox probe, analysis of the equivalent circuit model showed that the impedance change was primarily due to two elements: Double layer capacitance and resistance due to electrode surface roughness. The magnetic field and impedance were simulated using COMSOL Multiphysics software.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.

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