100A-25 |
Detection of Vibrio parahaemolyticus with a portable immunomagnetic focusing biosensor |
C. PALMER1, J. Ye1, A. G. Rand1, S. V. Letcher2, and C. M. Mello3. (1) Department of Food Science and Nutrition, University of Rhode Island, 530 Liberty Lane, W. Kingston, RI 02892, (2) Department of Physics, University of Rhode Island, East Hall, Kingston, RI 02881, (3) Biotechnology Team, Natick Soldier Systems Center, Natick, MA 01760 A major concern in seafood consumption is the contamination of seafood with harmful pathogenic bacteria such as V. parahaemolyticus. A rapid method is needed for monitoring the presence of the pathogen in seafood. The objective of this project was to adapt a portable immunomagnetic focusing biosensor that utilizes the specificity of antibodies and fast-binding antimicrobial Cecropin P1 peptides for rapid detection and quantification of V. parahaemolyticus. Samples containing V. parahaemolyticus were incubated with anti-V. parahaemolyticus coated magnetic beads for 1 h. After rinsing the magnetic beads, Cecropin P1 conjugated with CY5 fluorescent dye was added to form sandwich complexes after 30 min incubation with bound V. parahaemolyticus. The magnetic beads were rinsed 3 times, and then resuspended in 1 ml buffer. The magnetic bead sample was placed in the biosensor and focused in front of the dual fiber optic magnetic probe. The fluorescent signal excited by the laser light from one fiber and collected by the second fiber was used to determine the V. parahaemolyticus concentrations. The net fluorescent signal ranged from 543 to 8755 counts, corresponding to concentrations of V. parahaemolyticus from 6.0 x 104 to 5.8 x 106 CFU/ml. A linear regression model with R2=0.944 was established for a calibration curve over the detection range. The magnetic focusing biosensor was selective to V. parahaemolyticus in the presence of other pathogens in the sample, including S. typhimurium and E. coli O157:H7. The total assay procedure was completed within 2 h. The portable biosensor could provide a rapid method for detection of V. parahaemolyticus in seafood and demonstrated the potential use of an antimicrobial peptide for sandwich immunoassay labeling.
Session 100A, Food Microbiology: General II
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