Fluidic devices, systems, and methods for encapsulating and partitioning reagents, and applications of same

A method for partitioning microcapsules, comprising:

• (a) providing a microfluidic device comprising a microfluidic channel network, wherein the microfluidic channel network comprises (i) a droplet generation junction, (ii) a first channel segment fluidly connecting a source of microcapsules to the droplet generation junction, (iii) a second channel segment fluidly connecting a source of partitioning fluid to the droplet generation junction, and (iv) a third channel segment fluidly connected to the droplet generation junction and providing an outlet to the droplet generation junction;
• and
• (b) flowing (i) an aqueous fluid comprising a suspension of microcapsules from the source of microcapsules along the first channel segment and (ii) a partitioning fluid from the source of partitioning fluid along the second channel segment into the droplet generation junction to form a population of droplets of the aqueous fluid in the partitioning fluid, wherein the population of droplets flow along the third channel segment, and wherein (1) the first channel segment has a cross-sectional dimension that provides a flow rate of the aqueous fluid or (2) the second channel segment has a cross-sectional dimension that provides a flow rate of the partitioning fluid, such that greater than 50% of droplets of the population of droplets are occupied by microcapsules from the suspension of microcapsules.