Detection of E-coli O157:H7 using a miniaturized surface plasmon resonance biosensor

A commercially available Spreeta sensor was adapted into a surface plasmon resonance (SPR) biosensor to detect Escherichia coli O157:H7. The SPR biosensor couples antibody-antigen reactions with signal generation, using Kretschmann geometry to couple light into surface plasmons. The objectives of this study were to test the feasibility of adapting a miniaturized integrated SPR liquid sensing system into a biosensor to detect E. coli O157:H7 in laboratory cultures and to test its sensitivity and specificity. Experiments were conducted at near real-time with results obtained for one SPR biosensor assay within 35 min. The limit of detection for E. coli O157:H7 was determined to be 8.7 X 10(6) CFU/mL. In mixed cultures, the detection limit of the biosensor was 107 CFU/mL for E. coli O157:117 when the non-target bacterial concentration was 10(6) CFU/mL or less. Concentrations of non-target bacteria beyond 10(7) CFU/mL caused a decrease in the magnitude of the sensor response. The results of this study demonstrate the potential for employing the SPR biosensor to detect E. coli O157:H7 in near real-time. The SPR biosensor shows potential as a tool to assist the food industry in pathogen monitoring that is quick and specific. Due to its portability, it can potentially be incorporated into a HACCP protocol in the food industry.