Sort'N merge: A deterministic microfluidic platform for co-encapsulating distinct particles in microdroplets

This paper presents a microfluidic platform for deterministic co-encapsulation of desired combinations of distinct particles in individual droplets. Our microfluidic assay generates droplets co-encapsulating two and three different particles at a yield as high as 87.0% and 80.1%, respectively, by innovative integration of active droplet sorting and downstream merging processes. In conventional approaches, such integration is highly challenging due to the need for precisely handling a small amount of sorted droplets. The developed microfluidic platform is readily implemented for the co-encapsulation of multiple particles of a predetermined number in each droplet at high efficiency and high throughput. Our particle co-encapsulation technique eliminates stochastic pairing processes, for which the Poisson distribution severely limits the yield to < 10%.