first label-free carbohydrate-based electrochemical sensor to detectescherichia coli pathogenic bacteria using affinity between adhesionfimh and mannose on the glassy carbon electrode

Controlling water and food contamination by pathogenic organisms requires quick,simple, and low-cost methods. using affinity between mannose and type i fimbriaein the cell wall of escherichia coli (e. coli) bacteria as evaluation elements comparedto the conventional plate counting technique enables a reliable sensing platform forthe detection of bacteria. in this study, a simple new sensor based on electrochemicalimpedance spectroscopy (eis) for rapid and sensitive detection of e. coli wasdeveloped. biorecogniton layer of the sensor was formed by covalent attachment ofp-carboxyphenylamino mannose (pcam) to gold nanoparticles (aunps)electrodeposited on the surface of glassy carbon electrode (gce). the resultantstructure of pcam was characterized and confirmed using ftir. the developedbiosensor demonstrated a linear response with a logarithm of bacterial concentration(r2 = 0.998) in the range of 1.3 × 10 1~ 1.3 × 106 cfu.ml−1 with the limit of detectionof 2 cfu.ml−1 within 60 min. the sensor did not generate any significant signalswith two non-target strains, demonstrating high selectivity of the developedbiorecognition chemistry. selectivity of the sensor and its applicability to analysis ofthe real samples was investigated in samples of tap water and low-fat milk. overall,the developed sensor has shown to be promising for the detection of e. coli pathogenin water and low-fat milk due to its high sensitivity, short detection time, low cost,high specificity, and user-friendliness.