First label-free carbohydrate-based electrochemical sensor to detect Escherichia colipathogenic bacteria using affinity between adhesion FimH and mannose on the glassycarbon electrode

Controlling water and food contamination by pathogenic organisms requires quick, simple, andlow-cost methods. Using affinity between mannose and type I fimbriae in the cell wall of Escherichiacoli (E. coli) bacteria as evaluation elements compared to the conventional plate countingtechnique enables a reliable sensing platform for the detection of bacteria. In this study, a simplenew sensor based on electrochemical impedance spectroscopy (EIS) for rapid and sensitivedetection of E. coli was developed. Biorecogniton layer of the sensor was formed by covalentattachment of p-carboxyphenylamino mannose (PCAM) to gold nanoparticles (AuNPs) electrodepositedon the surface of glassy carbon electrode (GCE). The resultant structure of PCAMwas characterized and confirmed using FTIR. The developed biosensor demonstrated a linearresponse with a logarithm of bacterial concentration (R۲ = ۰.۹۹۸) in the range of ۱.۳ × ۱۰ ۱~ ۱.۳× ۱۰۶ CFU.mL−۱ with the limit of detection of ۲ CFU.mL−۱ within ۶۰ min. The sensor did notgenerate any significant signals with two non-target strains, demonstrating high selectivity of thedeveloped biorecognition 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 developedsensor has shown to be promising for the detection of E. coli pathogen in water and low-fatmilk due to its high sensitivity, short detection time, low cost, high specificity, and user-friendliness.

کلیدواژه ها:

Escherichia coli ، Electrochemical sensing ، D-mannose ، Electrochemical impedancespectroscopy ، Gold nanoparticles