Fig. 4.

Common methods and applications for droplet generation, including T-junctions, flow focusing, and co-flow. A Droplets generated using T-junctions. The channel facilitated fluid flow in one direction, and droplets were formed in the well because of restricted flow, adapted with permission from Wong et al. [98]. B Droplets generated using flow focusing. In the droplet generator, single cells were mixed with lysis buffer and encapsulated into aqueous droplets in an oil-based emulsion, adapted with permission from Hosokawa et al. [99]. C Droplets generated using co-flow. Cell-enclosing droplets can be obtained from a high viscous aqueous solution under ambient co-flowing liquid, adapted with permission from Sakai et al. [100]