Figure 4.

Use of the pumping lid approach to control pumping of each of several fluids with different properties in a microfluidic device. (A) Schematic of the pumping approach using multiple solutions in the same device. Each sample was pumped in the device with a different pumping lid, each lid producing a different pressure. (B) Left: Experimental photographs illustrating production of nanoliter plugs (red) in fluorinated oil (transparent), using a microfluidic device with flow focusing geometry. Right: Production of multicomponent aqueous droplets in fluorinated oil using a T-junction. The solutions (red, transparent and green) were pumped independently and used to produce nanoliter plugs. (C) Experimental photographs illustrating that the parallel laminar flow profile of three separate streams of aqueous solution (red, transparent and light blue) was stable even after 165 min (2.75 h). A total volume of 0.9 mL (300 μL of each solution) was pumped in this experiment.