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Proceedings Paper

An optical biosensor for detection of pathogen biomarkers from Shiga toxin-producing Escherichia coli in ground beef samples
Author(s): Loreen Lamoureux; Peter Adams; Afsheen Banisadr; Zachary R. Stromberg; Steven Graves; Gabriel Montano; Rodney Moxley; Harshini Mukundan
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Paper Abstract

Shiga toxin-producing Escherichia coli (STEC) poses a serious threat to human health through the consumption of contaminated food products, particularly beef and produce. Early detection in the food chain, and discrimination from other non-pathogenic Escherichia coli (E. coli), is critical to preventing human outbreaks, and meeting current agricultural screening standards. These pathogens often present in low concentrations in contaminated samples, making discriminatory detection difficult without the use of costly, time-consuming methods (e.g. culture). Using multiple signal transduction schemes (including novel optical methods designed for amphiphiles), specific recognition antibodies, and a waveguide-based optical biosensor developed at Los Alamos National Laboratory, we have developed ultrasensitive detection methods for lipopolysaccharides (LPS), and protein biomarkers (Shiga toxin) of STEC in complex samples (e.g. beef lysates). Waveguides functionalized with phospholipid bilayers were used to pull down amphiphilic LPS, using methods (membrane insertion) developed by our team. The assay format exploits the amphiphilic biochemistry of lipoglycans, and allows for rapid, sensitive detection with a single fluorescent reporter. We have used a combination of biophysical methods (atomic force and fluorescence microscopy) to characterize the interaction of amphiphiles with lipid bilayers, to efficiently design these assays. Sandwich immunoassays were used for detection of protein toxins. Biomarkers were spiked into homogenated ground beef samples to determine performance and limit of detection. Future work will focus on the development of discriminatory antibodies for STEC serotypes, and using quantum dots as the fluorescence reporter to enable multiplex screening of biomarkers.

Paper Details

Date Published: 2 March 2015
PDF: 8 pages
Proc. SPIE 9310, Frontiers in Biological Detection: From Nanosensors to Systems VII, 931004 (2 March 2015); doi: 10.1117/12.2079658
Show Author Affiliations
Loreen Lamoureux, The Univ. of New Mexico (United States)
Los Alamos National Lab. (United States)
The New Mexico Consortium (United States)
Peter Adams, Los Alamos National Lab. (United States)
Afsheen Banisadr, Los Alamos National Lab., Physical Chemistry and Applied Spectroscopy (United States)
Zachary R. Stromberg, Univ. of Nebraska-Lincoln, Ctr. for Veterinary Medicine and Biomedical Sciences (United States)
Steven Graves, The Univ. of New Mexico (United States)
Gabriel Montano, Los Alamos National Lab. (United States)
Rodney Moxley, Univ. of Nebraska-Lincoln, Ctr. for Veterinary Medicine and Biomedical Sciences (United States)
Harshini Mukundan, Los Alamos National Lab. (United States)
The New Mexico Consortium (United States)


Published in SPIE Proceedings Vol. 9310:
Frontiers in Biological Detection: From Nanosensors to Systems VII
Benjamin L. Miller; Philippe M. Fauchet; Brian T. Cunningham, Editor(s)

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