This video demonstrates the generation of salt-based aqueous microdroplets within an aqueous flow. The surrounding fluid is a water-based polymer solution, polyethylene glycol (PEG), while the inner fluid is a salt solution of magnesium sulfate. Creating aqueous droplets in an aqueous solution—a system known as an aqueous two-phase system (ATPS)—poses significant challenges due to low interfacial tension. This work presents a pioneering method for forming ATPS droplets ranging from 20 to 60 μm, successfully encapsulating human umbilical vein endothelial cells. The inset features the experimental setup and a schematic diagram illustrating the fluid arrangement in a flow-focusing geometry.