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Biosensors 2015, 5(1), 69-84;

Optimization of Electrically Active Magnetic Nanoparticles as Accurate and Efficient Microbial Extraction Tools

Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, 275 Slappy Drive, Hamilton, GA 31811, USA
Department of Biosystems and Agricultural Engineering, Michigan State University, 115 Farrall Hall, East Lansing, MI 48824, USA
Author to whom correspondence should be addressed.
Academic Editor: Chung-Chiun Liu
Received: 5 November 2014 / Revised: 18 December 2014 / Accepted: 23 January 2015 / Published: 5 February 2015
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Food defense requires the means to efficiently screen large volumes of food for microbial pathogens. Even rapid detection methods often require lengthy enrichment steps, making them impractical for this application. There is a great need for rapid, sensitive, specific, and inexpensive methods for extracting and concentrating microbial pathogens from food. In this study, an immuno-magnetic separation (IMS) methodology was developed for Escherichia coli O157:H7, using electrically active magnetic nanoparticles (EAMNPs). The analytical specificity of the IMS method was evaluated against Escherichia coli O55:H7 and Shigella boydii, and was improved over previous protocols by the addition of sodium chloride during the conjugation of antibodies onto MNPs. The analytical sensitivity of the IMS method was greatest when a high concentration of antibodies (1.0 mg/mL) was present during conjugation. EAMNP concentrations of 1.0 and 0.5 mg/mL provided optimal analytical sensitivity and analytical specificity. The entire IMS procedure requires only 35 min, and antibody-conjugated MNPs show no decline in performance up to 149 days after conjugation. This analytically sensitive and specific extraction protocol has excellent longevity and shows promise as an effective extraction for multiple electrochemical biosensor applications. View Full-Text
Keywords: microbial pathogens; immune-magnetic separation; biosensor; magnetic nanoparticles microbial pathogens; immune-magnetic separation; biosensor; magnetic nanoparticles

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Cloutier, B.C.; Cloutier, A.K.; Alocilja, E.C. Optimization of Electrically Active Magnetic Nanoparticles as Accurate and Efficient Microbial Extraction Tools. Biosensors 2015, 5, 69-84.

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