Improved Detection Techniques for Foodborne Pathogens: Development of Biosensors

Investigator: Rashid Bashir (Department of Bioengineering)

Project Report 2008 - 2009

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Project Rationale

We are using microfluidics and nanotechnology to develop rapid, sensitive, and selective biosensors for the detection of foodborne pathogens, such as Listeria monocytogenes. Our goal is to develop microfluidic biochips for rapid electrical detection of bacterial growth activity, and label-free electrical detection of nucleic acid molecules, especially Polymerase Chain Reaction (PCR) amplicons. This work can potentially have a significant impact on food safety by enabling the detection of foodborne pathogens using biochip-based point-of-test sensors.

Project Objectives

  • Integrate molecular recognition through real-time PCR assays on the biochip. Use microfabrication techniques to assemble multi-channel configurations on the biochip, which will enable multiple assays to be performed.
  • Develop label-free detection strategies to measure the progression of PCR with Dielectrophoresis (DEP)-based concentrations of nucleic acids using impedance-based detection of nucleic acid amplification.

Project Highlights

This year we demonstrated label-free electrical detection of PCR products using impedance measurement techniques. We were able to show that as little as 1 ug L. monocytogenes can be detected from cell lysate. We targeted the prfA 508 bp long gene using primers and measured the changes in the impedance of the solution with the amplified product after 25-30 cycles. We also detected L. monocytogenes in a mix of Escherichia coli O157:H7 and Listeria innocua in selectivity experiments using these techniques.

""This work can potentially have a significant impact on food safety by enabling the detection of foodborne pathogens using biochip-based point-of-test sensors.""

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