High-Performance E. coli Antibody-Conjugated Gold Nanorods for the Selective Electrochemical Detection of Pathogens in Drinking Water

The presence of microorganisms in water and food products is a chronic problem worldwide. This study attempts to develop pathogenic bacteria detection strategies using anti body-decorated gold nanorods (Au-NRs-Avidin-Ab- E ) by electrochemical analysis. Escherichia coli ATCC 25922 was detected as the target with the antibody-modified Au-NRs. Cyclic voltammetry (CV) measurements were run on the Au-NRs-Avidin-Ab- E. coli immobilized on the surface of a screen-printed carbon electrode (SPCE) to capture the E. coli. The correlation between the different bacteria concentrations indicated excellent electrocatalytic activity within the linear range of 10 1 CFU/mL to 10 5 CFU/mL ( R 2 = 0.990), with a limit of detection (LOD) of 0.37 CFU/mL for the target. Findings revealed that electrochemical detection of the bacteria was enhanced after the deposition of antibody onto Au nanorods. The tailor-made approach offered multiple benefits, such as large sensing surface area and increased electron transfer abilities compared to the bare electrode. The developed dispersive electrode has potential selectivity towards the targeted bacteria among different bacteria electrochemically characterized. The developed E. coli ATCC 25922 antibody-based system optimized the sensing of the targeted bacteria in the presence of other bacteria, in particular E. coli O157/H7, Salmonella typhimurium , and Vibrio cholera , in real water samples.