RFID Bacterial Sensor Tags

Task A: Binding Mechanisms: [A1] phages will be selected for binding to Salmonella bacteria and different methods of attaching the phages to the sensor surface investigated; [A2] investigate stripping receptor proteins from the phages for Salmonella and immobilizing these receptor phages on the surface of a thickness shear mode resonator as an alternate technique to antigen-antibody binding; and [A3] improve the antigen-antibody binding process Task B: Minaturized Sensor Platforms: [B1] piezoelectric drive and measured microcantilever beams; [B2] piezoresistive microcantilever beams; [B3] shear horizontal acoustic wave devices; and [B4] other inexpensive miniaturizable devices.
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Food safety is a national priority which affects every man, woman and child. A crucial part of a prevention strategy to lower the high incidence of foodborne illness is to employ methods that can rapidly detect the presence of toxins and pathogenic bacteria in food products. This research project is focused on the development of RFID (radio-frequency identification) sensor tags for the detection of foodborne bacteria such as Salmonella typhimurium. These RFID sensor tags would be placed on each and every food product sold in the United States, providing all or some of the following resources: automatic inventory, product time and temperature monitoring, and instantaneous traceability.
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PROGRESS: 2004/01 TO 2004/12<br>
The U.S. food system has evolved to be the envy of the world. This system is highly efficient and provides American consumers with one of the most diverse, abundant and economical food supplies in the world. The development of radio frequency identification sensor tags or RFID Stags will greatly improve the safety and security of our food supply. The ultimate objectives of this project is to take the sensing methodologies developed and demonstrated under USDA grant ALA-070-001 and ALA-070-005 and combine them with electronics to create a hand held detection device for the identification of pathogenic bacteria and spores in the field. This year two major advancements have been made in research toward development of RFID sensor tags for advancing food safety and security. Phage as a substitute for Antibody Detection. AUDFS successfully developed phage for the binding of Salmonella typhimurium and Bacillus anthracis. Comparison of the binding characteristics of the phage with the best commercial antibodies showed that the phage outperformed antibodies with higher binding affinity, greater specificity and much improved longevity and stability. Both the phage for Salmonella typhimurium and Bacillus anthracis were found to have a binding affinity at least 2 times that of the best antibodies. Three major factors were found to contribute to the high binding affinity of Auburn's landscape phage. These factors are: constrained conformation of binding peptides, multivalent display of the binding receptors and extremely high local concentration of binding sites. The specificity of Auburn's phage for Bacillus anthracis was examined. The binding to anthracis spores is several orders of magnitude greater than other similar bacillus spores. The phage after 45 days at 65 degrees C shows greater binding affinity than the antibody at the start of the high temperature exposure test. The antibody lost all binding affinity after 3 to 5 days of exposure at 65 degrees C. All of this research on characterization of the phage was done using magnetostrictive particles as the substrate for the biosensor. Magnetostrictive Particles as a Platform for Detection. A milestone objective in the research to develop magnetostrictive particles for use as a platform has been reached. We have been able to fabricate, using microelectronics fabrication procedures, particles 10 x 50 microns in size. With this size particle we should be able to detect the binding of a few spores or bacteria to the surface of the sensor. The objectives for next year will be to demonstrate detection of single cell binding.
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IMPACT: 2004/01 TO 2004/12<br>
Food safety is a national priority which affects every man, woman and child. A crucial part of a prevention strategy to lower the high incidence of food borne illness is to employ methods that can rapidly detect the presence of toxins and pathogenic bacteria in food products. This research project is focused on the development of a hand-held sensor for the detection of food borne bacteria such as Salmonella typhimurium and Bacillus Anthracis Sterne Strain spores. Bacillus Anthracis Sterne Strain spores are a potential terrorism agent that may be spread rapidly throughout the food chain. Our consortium will develop methods of detecting spores within 100 seconds at a detection limit of a few thousands of cells per ml of liquid.
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PROGRESS: 2003/01/01 TO 2003/01/31<br>
The U.S. food system has evolved to be the envy of the world. This system is highly efficient and provides American consumers with one of the most diverse, abundant and economical food supplies in the world. The development of radio frequency identification sensor tags or RFID Stags will greatly improve the safety and security of our food supply. The ultimate objectives of this project is to take the sensing methodologies developed and demonstrated under USDA grant ALA-070-001 and ALA-070-005 and combine them with electronics to create a hand held detection device for the identification of pathogenic bacteria and spores in the field. This year two major advancements have been made in research toward development of RFID sensor tags for advancing food safety and security. These discoveries are: Phage as a Substitute for Antibody Detection. An antibody is a relatively fragile species and subject to denaturation with consequential loss of sensitivity and other binding characteristics when exposed to unfavorable environments. Moreover, the quality of antibodies can vary with different animals and production variables. To be used in biosensors, antibodies require affinity purification and stabilization, which dramatically increase their cost. The use of phage as substitute antibodies offers a stable, reproducible and inexpensive alternative. The Auburn University Detection and Food Safety Center has successfully developed phage for the binding of Salmonella typhimurium. Three major factors contribute to the high affinity binding of landscape phage to their targets: a) constrained conformation of foreign peptides; b) their multivalent display, thousands of binding sites/phage filament; and c) extremely high local concentration of binding sites. The surface area density of the phage is 300 to 400 m2/g, exceeding probably the best-known absorbents and catalysts. Biosensor surfaces that have been coated with antibody and phage for binding of S. typhimurium. Both biosensor surfaces were exposed, under similar conditions, to the same PBS solution containing S. typhimurium bacteria at a concentration of 108 CFU/ml. The phage coated biosensor showed a much higher binding of S. typhimurium bacteria than does the antibody coated biosensor. Magnetostrictive Particles, a new detection method. Auburn University's Detection and Food Safety Center has developed a continuous method of monitoring for pathogenic bacteria, viruses and toxins in both gaseous and liquid media. The methodology employs MagnetoStrictive Particles (MSPs) that have been coated, impregnated or chemically bound with receptors (phage, antibodies, DNA, enzymes, etc.) that serve to recognize and bind the target pathogens/toxins. The MSPs are suspended in the stream of the flowing analyte and driven into resonance using an external magnetic field. Target species in the analyte are specifically recognized and bound to the surface of the MSPs by the phage, antibody, etc. When binding occurs, a change in the resonance frequency of the MSPs results. MSPs are evaluated for binding in-situ, in real time by remote, wireless measurement.
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IMPACT: 2003/01/01 TO 2003/01/31<br>
Food safety is a national priority which affects every man, woman and child. A crucial part of a prevention strategy to lower the high incidence of food borne illness is to employ methods that can rapidly detect the presence of toxins and pathogenic bacteria in food products. This research project is focused on the development of a hand-held sensor for the detection of food borne bacteria such as Salmonella typhimurium and Bacillus Anthracis Sterne Strain spores. Bacillus Anthracis Sterne Strain spores are a potential terrorism agent that may be spread rapidly throughout the food chain. Our consortium will develop methods of detecting spores within 100 seconds at a detection limit of a few thousands of cells per ml of liquid.