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From: The eUpdate, 4.26.2011
New Biosensor Could Speed Pathogen Detection
Array of tiny electrodes generates an identifiable electrical signal
A new nanotechnology-based biosensor now under development is another entry in the ever-growing race to speed the detection of pathogens such as E. coli, Salmonella, and Listeria in food and water supplies.
Lateef Syed, Kansas State University
A goal is to integrate this technology into a hand-held electronic device for pathogen detection so that we can use this device for in-line monitoring of water quality or food quality at industrial processing sites.
The development involves a partnership between researchers at Kansas State University and a Canadian company called Early Warning, Inc., a spinoff from NASA’s Ames Research Center in California’s Silicon Valley. While working at NASA, Jun Li, PhD, developed the idea of creating a small chip that would capture and detect pathogens. Now an associate professor of chemistry at Kansas State University in Manhattan, Dr. Li has been working in partnership with chemistry doctoral student Lateef Syed to create biosensors based on carbon nanofibers, which form an array of electrodes even smaller than bacteria and viruses. When such microbial particles are captured at the electrode surface, they generate an identifiable electrical signal.
"A goal is to integrate this technology into a hand-held electronic device for pathogen detection so that we can use this device for in-line monitoring of water quality or food quality at industrial processing sites," Syed said. "We have some preliminary results that indicate this technology is feasible."
Development efforts currently focus on the detection of E. coli in water, using a processing system that concentrates a large sample down to a few milliliters. “Reducing the sample, extracting the targets from the background material, using microfluidics to extract RNA, and then feeding that sample to our sensors—that whole process takes about four hours, and it’s able to detect the 0157.H7 strain from a cocktail of E. coli and heterotrophic bacteria,” said Neil Gordon, Early Warning’s CEO. “We believe that we can detect this and other pathogens such as Salmonella and Listeria down to very low concentrations, approximately one to 100 cells per sample, in about four hours. We hope to have a working prototype by the end of the year.”
The tap water process should easily translate to foodborne pathogen detection, Gordon said. “If the target medium is any liquefied solid, and we are able to extract our target organisms from background material that could interfere with detection, then it should be successful,” he added.
The research has been accepted for publication in an upcoming edition of the journal Electrophoresis.