Sensors 2006, 6(8), 796-807; doi:10.3390/s6080796
Article

Fiber-Optic Biosensor Employing Alexa-Fluor Conjugated Antibody for Detection of Escherichia coli O157:H7 from Ground Beef in Four Hours

1, 2, 2 and 1,* email
Received: 3 February 2006; Accepted: 12 April 2006 / Published: 19 August 2006
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Fiber optic biosensor has a great potential to meet the need for rapid, sensitive,and real-time microbial detection systems. We developed an antibody-based fiber-opticbiosensor to rapidly detect low levels of Escherichia coli O157:H7 cells in ground beef. Theprinciple of the sensor is a sandwich immunoassay using an antibody which is specific forE. coli O157:H7. A polyclonal antibody was first immobilized on polystyrene fiberwaveguides through a biotin-streptavidin reaction that served as a capture antibody. AnAlexa Fluor 647 dye-labeled antibody to E. coli O157:H7 was used to detect cells andgenerate a specific fluorescent signal, which was acquired by launching a 635 nm laser-lightfrom an Analyte-2000. Fluorescent molecules within several hundred nanometers of thefiber were excited by an evanescent wave, and a portion of the emission light fromfluorescent dye transmitted by the fiber and collected by a photodetector at wavelengths of670 to 710 nm quantitatively. This immunosensor was specific for E. coli O157:H7compared with multiple other foodborne bacteria. In addition, the biosensor was able todetect as low as 103 CFU/ml pure cultured E. coli O157:H7 cells grown in culture broth.Artificially inoculated E. coli O157:H7 at concentration of 1 CFU/ml in ground beef couldbe detected by this method after only 4 hours of enrichment.
Keywords: Escherichia coli O157:H7; fiber-optic biosensor; antibodies; detection; ground beef.
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MDPI and ACS Style

Geng, T.; Uknalis, J.; Tu, S.-I.; Bhunia, A.K. Fiber-Optic Biosensor Employing Alexa-Fluor Conjugated Antibody for Detection of Escherichia coli O157:H7 from Ground Beef in Four Hours. Sensors 2006, 6, 796-807.

AMA Style

Geng T, Uknalis J, Tu S-I, Bhunia AK. Fiber-Optic Biosensor Employing Alexa-Fluor Conjugated Antibody for Detection of Escherichia coli O157:H7 from Ground Beef in Four Hours. Sensors. 2006; 6(8):796-807.

Chicago/Turabian Style

Geng, Tao; Uknalis, Joe; Tu, Su-I; Bhunia, Arun K. 2006. "Fiber-Optic Biosensor Employing Alexa-Fluor Conjugated Antibody for Detection of Escherichia coli O157:H7 from Ground Beef in Four Hours." Sensors 6, no. 8: 796-807.

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