Herein, we present a microfluidic-based point-of-care testing approach for viable Escherichia coli detection in tap water. In this approach, antibody-modified magnetic particles were used for capturing E. coli from water, followed by concentrating the bacteria-bound particles in the device using an external magnet. Then, redox indicator reagent mixed culture medium was added into the device, which allows colorimetric signal change as a result of reduction reaction linked to bacteria proliferation. Corresponding color change was monitored from microfluidic access holes, which are named μ-pupil, in which the colorimetric signal can be recorded from the perspective view angles of the transparent device, and analyzed using a software. Concentrating sample in the small volume of the microfluidic device shortened the incubation period for the detection of viable E. coli. The correlation of the colorimetric signal and E. coli concentration showed linearity within the range of 8 × 103–8 × 105 CFU/ml E. coli and 8 × 100–8 × 103 CFU/ml E. coli after 6 h and 12 h of incubation at 37 °C, respectively. The filtration integrated μ-pupil method was found advantageous by processing large sample volumes that allows the detection of 2 CFU/100 ml E. coli after 12 h of incubation. The developed approached which enables wide-range concentrations of viable E. coli testing using portable components, including a temperature controlled mini-incubator and a mobile-phone based optical setup, can be useful for microbial testing of water in resource limited remote areas.
Date:
2022-07
Relation:
Microchemical Journal. 2022 Jul;178:Article number 107390.
