Figure 1.

A typical workflow of droplet-based high-throughput screening system for protein engineering. (A) Single cells are encapsulated into monodisperse water-in-oil droplets generated on a flow-focusing (left) or T-junction (right) nozzle. (B) Cell-laden droplets can be incubated either on-chip or off-chip and new reagents can be added via droplet coalescence. (C) Droplets of interest can be sorted either by fluorescence-activated cell sorting (FACS) after an extra step of double emulsification or by fluorescence-activated droplet sorting (FADS). Alternatively, the content of droplets of interest can be recovered via fluorescence-activated electrocoalescence (FAE).