Fully Automated System for Rapid Enrichment and Precise Detection of Enterobacteria Using Magneto-Electrochemical Impedance Measurements

The contamination of food and drinking water by bacteria that cause food poisoning is a critical public health issue. In general, the procedures for testing the presence of pathogenic bacteria in public is not very effective, because it is time consuming and does not facilitate real-time monitoring in a field setting. Therefore, this study introduced a fully automated platform that would allow non-experts to easily examine the major food poisoning bacteria in a field setting, from pretreatment samples to final detection. Two enterobacteria species, of four different bacteria species (i.e., Escherichia coli and Salmonella typhimurium) were successfully immobilized on the surface of magnetic beads by exploiting the specific binding force with mannose. Subsequently, magneto-electrochemical impedance measurement technology allowed bacterial detection with a high sensitivity. E. coli, typical enterobacteria, was detected in 25 min with a detection limit of 100 CFU/mL. Moreover, we demonstrated that the automatic performance and the experimental consistency was greatly improved in comparison with those of manually conducted experiments.