Sensitive detection of multiplex bacteria based on finger driven microfluidics and recombinase aided amplification.

Foodborne pathogens, such as Salmonella typhimurium, E. coli O157:H7 and Listeria monocytogenes, have seriously threatened human health. To address the issues of traditional bacterial detection methods, such as long time, low sensitivity and complex operation, a versatile finger driven microfluidic chip was elaboratively developed and combined with recombinase aided amplification for fast, sensitive and simple detection of multiplex bacteria. In the microfluidic chip, three pneumatic check valves were designed to coordinate with their respective air chambers for transferring their corresponding solutions to their designated destinations, and a 3D-printed rotating valve was developed to select the designated solution to flow towards the designated direction. Besides, a portable device with a LED light as excitation source was developed to detect the fluorescent signals for bacterial quantification. Under the optimal conditions, the microfluidic chip could detect Salmonella typhimurium, E. coli O157:H7 and Listeria monocytogenes as low as 15 CFU/mL, 48 CFU/mL and 38 CFU/mL within 45 min. It was featured with simple operation, high sensitivity and short time, and showed the potential for in-field screening of foodborne pathogens to enhance food safety.