Bacterial pathogens are universally present in the environment and could easily contaminate food and water to cause serious food-borne illnesses. Early identification of these pathogens at ultra-low levels of contamination could help us ensure food quality and prevent the major outbreaks of food-borne diseases. Electrochemical biosensors offer unique advantages for pathogen identification including rapid detection, high sensitivity, and easy-to-use testing procedure. The specificity and the cost of the biosensor are mostly dependent on the type and nature of the bio-recognition element used in biosensors. Although enzymes and antibodies are commonly used as bio-recognition molecules, they are highly susceptible to surrounding environment and are less stable on electrode surfaces. While Bacteriophages, on the other hand, are ubiquitous in nature and possess robust stability. Herein, bacteriophage has been explored as an alternative bio-recognition element for the detection of pathogenic bacteria. More specifically, a wild type T2 phage was utilized as the recognition element for direct detection of Escherichia coli, ATCC 11303. The T2 phages were immobilized on carbon nanotube modified glassy carbon through charge-directed molecular tethering immobilization approach. The presence of the immobilized phage on carbon nanotube modified electrode was confirmed by fluorescence microscopy. Electrochemical impedance spectroscopy was used to monitor the impedance variations resulting from the binding of E. coli to T2 phage. The phage-based biosensor showed high sensitivity towards the detection of E. coli, while the controls in the absence of phage did not show any signal for the E. coli detection.

Charge-directed immobilization of bacteriophage on nanostructured electrode for whole cell electrochemical biosensors

253rd National Meeting (2017)

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