Point-of-care detection of O157:H7 in water using AuNPs-based aptasensor.

OBJECTIVES

Access to safe drinking and irrigation water has always been one of the major human concerns worldwide. Thus, rapid, sensitive, and inexpensive approaches for pathogenic bacteria detection, such as O157:H7 (EHEC) that can induce important infectious diseases, are highly on demand.

MATERIALS AND METHODS

In this study, a sensitive aptamer-based AuNPs bioassay was developed that demonstrated its potential to detect EHEC. In the presence of the target bacterium, the specific adsorbed aptamer, leaves AuNPs surface and interacts with EHEC. The bare nanoparticles aggregate in the presence of NaCl and the color shifts from red to purple and blue depending on the bacterial concentration.

RESULTS

The proposed aptasensor exhibited a good linear response over a wide concentration range of 876 to 107 CFU/ml and was closely correlated with the line equation of "y=0.0094x+0.0006" (R2= 0.9861). It also showed a low detection limit (LOD) of 263 CFU/ml (Signal/Noise=3). No response was recorded in the presence of other tested bacterial strains including and , indicating the high selectivity of the aptasensor.

CONCLUSION

This biosensor may be used as a smart device to screen water reservoirs and prevents the outbreak of EHEC-related life-threatening contagious diseases.