Bacterial cell transportation in paper-based microfluidics

In this work, we provided a new technique to monitor the flow of bacterial cells in paper. This was based on real-time measuring of the electricity generated from bacterial metabolism. Despite recent efforts to monitor liquid flow in paper, there is not yet a technique that provides detailed flow information of particles in paper microfluidics. Our device contained three hydrophilic spots linked by a hydrophilic channel on paper. Each spot came into contact with an anode that was electrically connected to a cathode through an external load. When bacterial cells were transported to each spot by capillary force, the current generated from the bacteria was monitored and bacterial cells´ transportation through the channel was quantitatively investigated according to the pore size of the paper.