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<OL><LI> To provide an understanding of fundamental nanoscale phenomena and processes. <LI> To develop and characterize nanomaterials. <LI>To develop nanoscale devices and systems.<LI> To provide an understanding of economic, environmental, safety and health impacts of nanotechnology in agricultural, food and biological systems.<LI>To develop educational and outreach programs on the use and impacts of nanotechnology in food, agricultural and biological systems.
Non-Technical Summary: Nanobeads and nanofibers will be studied for highly efficient immunoseparation and highly sensitive impedance measurement in order to develop a nano-biosensor for rapid detection of foodborne pathogens including Salmonella, Listeria and E. coli in poultry, meat and vegetables. A prototype nano-biosensor will be designed, fabricated, tested and evaluated for its applications in agriculture and foods. <P> Approach: By integrating the high efficiency of nanobeads-based sample separation/concentration, the high sensitivity of nanowire/nanofibers, and the high efficacy of flow-through microfluidics channel into the design, we will develop a nano-biosensor that will meet the required sensitivity, specificity, and speed for screening of foodborne pathogens in different foods. The specific objectives of this proposed research are as follows: (1) Develop an immunoseparation method based on magnetic nanobeads coated with specific antibodies to separate target bacteria in a food sample and concentrate them for use in the biosensor; (2) Design and fabricate immuno-nanofibers based microelectrodes as a novel sensor platform to improve detection sensitivity and reduce assay time; and (3) Evaluate the biosensor for detecting Listeria monocytogenes, Salmonella Typhimurium and E. coli O157:H7in poultry and other meat products and fresh vegetable samples. The biosensor will consist of a sampler, multiple-section microfluidic cartridges, a pumping unit, an impedance detector, a microprocessor, a display, a key panel, and a USB connector. When a food sample, containing various biological and chemical components and different bacteria, is dropped, it is mixed with magnetic nanobeads (10-100 nm) coated with antibodies for 5 to 15 min to get sufficient immunoreaction. Then, target bacteria are separated by applying a magnetic field to hold magnetic beads while washing. During their flowing through a microfluidic channel (20x100 um cross-section), target bacteria are captured by the antibodies immobilized on the nanowire/nanofibers (10-50 nm) connected to two microelectrodes (5 to 15 min). Free nanobeads can pass through the nanofibers. The change in dielectric properties of the nanowire/nanofilber, i.e., impedance, caused by captured target bacteria, is measured and correlated to the cell number of bacteria in a food sample.