Abstract: The present technology generally relates to stopped-flow microfluidic devices. Select embodiments of the present technology include microfluidic devices having a first porous element configured to receive a first fluid and a second porous element configured to receive a second fluid. The second porous element can have one or more legs overlapping with the first porous element. The device can be configured such that (a) delivery of the first fluid to the first porous element causes the first fluid to flow along the length of the first porous element without substantially wetting the one or more legs, and (b) delivery of the second fluid to the second porous element causes the second fluid to flow into the overlapping regions of the first porous element, thereby substantially stopping flow of the first fluid along at least a portion of the first porous element.