Device and method for pressure-driven plug transport and reaction

A method comprising:

• a microfluidic device comprising a substrate having a plurality of traps in fluidic communication with a channel, each trap comprises an opening along a side of the channel shaped and/or sized to accommodate a partition of a sample fluid within;
• introducing a sample fluid into the channel of the device via an inlet, the sample fluid comprising a target molecule;
• introducing a fluid immiscible with the sample fluid into the channel via the inlet;
• positioning a plurality of partitions of sample fluid within the plurality of traps in response to flow of the immiscible fluid through the channel and displacement of the sample fluid;
• and
• monitoring each partition of sample fluid retained within a corresponding trap, wherein monitoring comprises detecting emissions from one or more detectable markers associated with a target molecule in response to the occurrence of a polymerase-chain reaction (PCR) reaction in one or more partitions of sample fluid.