4/11/02

Michael Tullier, 334/844-3419.

-- AU Peaks of Excellence --

'LANDSCAPE PHAGES' OFFER NEW HORIZON OF DETECTION CAPABILITIES

AUBURN -- Landscape phage might be considered as a new type of submicroscopic "fiber," with the potential of replacing the function of antibodies in a multitude of diagnostic applications. This could include the foundation for foodborne contaminant testing occurring in Auburn University's Detection and Food Safety Center, and even many laboratory-based tests.

Like most laboratory testing, detection systems designed by AUDFS use antibodies collected from animals and specially designed for a specific laboratory function. These antibodies are then integrated into diagnostic test kits or testing materials. Since 1999, AUDFS researchers have been designing a system to detect foodborne contaminants like Salmonella and E. coli using stamp-sized radio-frequency sensors designed around the use of antibodies. The introduction of phage technology may now offer additional detection opportunities and applications by the research center.

Bacteriophages are produced in the laboratory by using a bacterium as a host to grow them. Each phage clone is a type of fiber with unique surface properties. Billions of fibers are constructed, propagated all at once in a single vessel, and distributed in portions to multiple end-users with many different goals.

Valery Petrenko, a Russia pioneer of phage technology, joined the AU faculty in January 2001 as a member of the AUDFS research team and professor in the College of Veterinary Medicinešs Department of Pathobiology. His research brings an entirely different possibility to detecting foodborne contaminants.

"Current detection methods involve antibodies, which have limitations," says Petrenko. "Our phages, as selected recognition elements, give more possibilities and can function in different unfavorable environments. We believe the phage is a perfect material for fabrication of bio-selective layers in biosensors."

Petrenko's collaboration within AUDFS is the first demonstration of the use of landscape phages as bio-selective elements for biosensors, for which the center is now seeking patent-protection status. As substitutes for antibodies, phages demonstrate many features, such as high affinity for the analyte, field stability and low cost. These novel new bioselective elements allow for the development of a new generation of biosensors for food safety, as well as applications within the health care, pharmaceutical, diagnostic and law enforcement sectors.

The AU Detection and Food Safety Center is working on detection systems for Salmonella, E. coli, and a host of other foodborne pathogens that infect more than 76 million Americans every year, hospitalize more than 325,000 people and kill more than 5,200 people. In addition, AUDFS researchers are concentrating efforts on detecting animal feed contaminants that could lead to the transmission of bovine spongiform encephalopathy (BSE, or "mad cow disease"). While "mad cow disease" has not been detected in the United States, it has run rampant in Europe. Initially detected in the United Kingdom in 1986, BSE had infected nearly 200,000 head of cattle, and has now resulted in the destruction of more than three million more, by the end of 2001

"Obviously, 'mad cow disease' represents a looming threat to the purity of the U.S. food supply," Bryan Chin, AUDFS center director, says. "The spread of this disease in Europe has shown that every step must be made in preventing, not reacting to, this threat."

In the AUDFS detection system, stamp-sized radio-frequency sensor tags will be placed on the surface or in the packaging of foods such as poultry, beef, vegetables, juices and milk. The sensors will communicate by radio frequency with receivers placed at critical points along the food-supply chain, including food processing plants, transportation vehicles, distribution centers and retail locations. The sensors will contain valuable food processing, storage and transportation information, as well as possess the capability to alert handlers and retailers of rising levels of foodborne contamination by Salmonella, E. coli, Listeria and Campylobacter. Contaminated food can then be removed from the food-supply chain, preventing dozens -- or even thousands -- of people from being infected.

AUDFS' multidisciplinary research team includes more than 20 core and affiliate faculty members from five AU colleges: Agriculture, Engineering, Human Sciences, Sciences and Mathematics, and Veterinary Medicine. It continues to work toward an antibody-based handheld detector for Salmonella, which it expects to complete by year's end. While its current Salmonella and E. coli detector research is still antibody-driven, the use of phage in this same manner is being integrated into future generations of foodborne and feed-based contaminant research.

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