Rapid detection and quantification of bacteria using an integrated micro/nanofluidic device

In this study, we present an integrated micro/nanofluidic device that integrates a micromixer and a preconcentrator for the rapid detection of bacteria. The micromixer based on the concept of unbalanced splits and cross-collisions of fluid streams is used for mixing bacterial cells with tagging molecules. The preconcentrator consists of two microchannels (main and sub) that are connected by the nanochannels, which can be easily fabricated by electric breakdown of a ∼25 μm-thick polydimethylsiloxane (PDMS) membrane using high electric shock. Escherichia coli (E. coli) sample is tagged with fluorescent dye and continuously preconcentrated at the target position by applying the electric field through the junction of micro- and nanochannels. The concentration of bacterial sample can be quantified by measuring the fluorescence intensity at the preconcentrated region.