36B-8 |
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S. R. NUGEN, Food Science, Cornell Univ., 1018 Bradfield Hall, Ithaca, NY 14853, A. J. Baeumner, Dept. of Biological & Environmental Engineering, Cornell Univ., 318 Riley-Robb Hall, Ithaca, NY 14853-5701, C. Siryk, Biological & Environmental Engineering, Cornell University, 1018 Bradfield Hall, Ithaca, NY 14853, and K. Edwards, Toxicology, Cornell Unicersity, 1018 Bradfield Hall, Ithaca, NY 14853. E. coli is often used as an indicator organism for food contamination. The development of a reliable and more rapid biosensor for E. coli could prove a very useful tool for reducing foodborne illness outbreaks. Traditional nucleic acid-based biosensors utilize amplification methods such as NASBA or PCR to obtain low limits of detection, however these steps are often the most time consuming and expensive step of the assay and eliminating them could result in a much less expensive and very rapid biosensor. The objective of this project is to design a biosensor that avoids lengthy gene amplification methods, yet obtains low limits of detection desired. In this study we developed a biosensor that uses liposome amplification in combination with multiple detection probes resulting in a rapid, specific and highly sensitive biosensor.Lateral flow assays were developed for the initial investigations. DNA reporter probes were tagged with dye-encapsulating liposomes. These “reporter” probes were designed to specifically hybridize with the target E. coli RNA. Biotinylated DNA oligonucleotides were used as capture probes. Multiple RNA sequences were selected as targets. Within each RNA multiple hybridization sites were chosen in order to obtain a high number of hybridization events and thus high signal amplification via liposomes per E. coli cell. Promising results were obtained that will lead to the possibility of detecting less than 100 cells of E. coli in just 30 min. with a rugged biosensor that does not require any incubation or gene amplification methods and will therefore be very inexpensive and simple to use. The lateral-flow assay will be integrated into an electrochemical microbiosensor in order to further decrease the limit of detection. Biosensors could prove very useful in food processing plants for examining raw materials, finished goods, or ensuring sanitation of the production equipment. Without the need of gene amplification systems, biosensors will become less dependent on sample preparation steps, will be much less costly and will be easier to use.
Session 36B, Biotechnology: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |