An optical biosensor for detection of pathogen biomarkers from Shiga toxin-producing Escherichia coli in ground beef samples

Loreen Lamoureux, Peter Adams, Afsheen Banisadr, Zachary Stromberg, Steven Graves, Gabriel Montano, Rodney Moxley, Harshini Mukundan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


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.

Original languageEnglish (US)
Title of host publicationFrontiers in Biological Detection
Subtitle of host publicationFrom Nanosensors to Systems VII
EditorsBrian T. Cunningham, Benjamin L. Miller, Philippe M. Fauchet
ISBN (Electronic)9781628414004
StatePublished - 2015
Externally publishedYes
EventFrontiers in Biological Detection: From Nanosensors to Systems VII - San Francisco, United States
Duration: Feb 7 2015 → …

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


ConferenceFrontiers in Biological Detection: From Nanosensors to Systems VII
Country/TerritoryUnited States
CitySan Francisco
Period2/7/15 → …


  • Amphiphilic pathogen biomarkers
  • Lipopolysaccharides (LPS)
  • Membrane insertion assays
  • Planar optical waveguide biosensor
  • Shiga toxin-producing Escherichia coli (STEC)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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