Electrochemical Biosensor for Rapid Detection of Listeria Monocytogenes

Listeria monocytogenes (L. monocytogenes) is a common foodborne pathogen that has been responsible for many foodborne illness outbreaks in recent years. Currently, Listeria contamination in food products is identified only through molecular tests conducted in diagnostic laboratories. No established phage based diagnostic methods for L. monocytogenes during food production or processing are used. Here we report a potentially disruptive rapid diagnostic method based on electrochemical biosensing principles that use bacteriophages as bioreceptors for selective identification and quantification of L. monocytogenes. Electrochemical biosensors are good alternatives to molecular detection methods due to their ease of use, high specificity, sensitivity, and low cost. Bacteriophages can serve as excellent biorecognition elements in biosensors due to their robust stability in a range of environmental conditions and their ability to distinguish between live and dead bacterial cells. The impedimetric biosensing platform for L. monocytogenes detection was developed by immobilizing P100 bacteriophage onto quarternized polyethylenimine modified carbon nanotubes using an in-house developed molecular tethering method. The resulting sensor showed high selectivity and sensitivity toward L. monocytogenes with a limit of detection of 8.4 CFU/ml. Initial results demonstrate that the biosensing platform is highly reliable in its selectivity towards its target analyte, L. monocytogenes.