A method for partitioning microcapsules, comprising: (a) providing a microfluidic device comprising a microfluidic channel network comprising: (i) a droplet generation junction and a first channel segment fluidly connected to the droplet generation junction, wherein the first channel segment is configured to receive an aqueous fluid comprising a suspension of microcapsules; (ii) a second channel segment (424,426) fluidly connected to the droplet generation junction, wherein the second channel segment (424,426) is configured to receive a partitioning fluid; and (iii) a third channel segment fluidly connected to the droplet generation junction; wherein the first channel segment comprises a flow regulator (436, 600), and wherein a cross-section of the flow regulator (436,600) broadens relative to the point a flow enters the flow regulator and then narrows along a direction of flow along the first channel segment towards the droplet generation junction; and (b) flowing (i) the aqueous fluid comprising the suspension of microcapsules along the first channel segment and through the flow regulator (436,600) and (ii) the partitioning fluid along the second channel segment (424,426), to 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 a flow rate of the aqueous fluid is such that no more than 50% of droplets of the population of droplets are unoccupied by a microcapsule of the suspension of microcapsules. (a) providing a microfluidic device comprising a microfluidic channel network comprising: (i) a droplet generation junction and a first channel segment fluidly connected to the droplet generation junction, wherein the first channel segment is configured to receive an aqueous fluid comprising a suspension of microcapsules; (ii) a second channel segment (424,426) fluidly connected to the droplet generation junction, wherein the second channel segment (424,426) is configured to receive a partitioning fluid; and (iii) a third channel segment fluidly connected to the droplet generation junction; wherein the first channel segment comprises a flow regulator (436, 600), and wherein a cross-section of the flow regulator (436,600) broadens relative to the point a flow enters the flow regulator and then narrows along a direction of flow along the first channel segment towards the droplet generation junction; and (i) a droplet generation junction and a first channel segment fluidly connected to the droplet generation junction, wherein the first channel segment is configured to receive an aqueous fluid comprising a suspension of microcapsules; (ii) a second channel segment (424,426) fluidly connected to the droplet generation junction, wherein the second channel segment (424,426) is configured to receive a partitioning fluid; and (iii) a third channel segment fluidly connected to the droplet generation junction; (b) flowing (i) the aqueous fluid comprising the suspension of microcapsules along the first channel segment and through the flow regulator (436,600) and (ii) the partitioning fluid along the second channel segment (424,426), to 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 a flow rate of the aqueous fluid is such that no more than 50% of droplets of the population of droplets are unoccupied by a microcapsule of the suspension of microcapsules.