A Label-Free Impedance Immunosensor Using Screen-Printed Interdigitated Electrodes and Magnetic Nanobeads for the Detection of E. coli O157:H7Report as inadecuate




A Label-Free Impedance Immunosensor Using Screen-Printed Interdigitated Electrodes and Magnetic Nanobeads for the Detection of E. coli O157:H7 - Download this document for free, or read online. Document in PDF available to download.

1

Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR 72701, USA

2

Cell and Molecular Biology Program, University of Arkansas, Fayetteville, AR 72701, USA

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College of Information and Electrical Engineering, China Agricultural University, Beijing 100083, China

4

Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA

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College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310068, China





*

Author to whom correspondence should be addressed.



Academic Editors: Nicole Jaffrezic-Renault and Carole Chaix

Abstract 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. View Full-Text

Keywords: immunosensor; magnetic nanobeads; impedance; screen-printed interdigitated electrode; E. coli O157:H7; rapid detection immunosensor; magnetic nanobeads; impedance; screen-printed interdigitated electrode; E. coli O157:H7; rapid detection





Author: Ronghui Wang 1, Jacob Lum 2, Zach Callaway 1, Jianhan Lin 3, Walter Bottje 4 and Yanbin Li 1,2,4,5,*

Source: http://mdpi.com/



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