Phase‐Separation‐Induced Formation of Janus Droplets Based on Aqueous Two‐Phase Systems

In this study, Janus droplets are fabricated by inducing phase separation of single‐phase droplets made up of an aqueous two‐phase system (ATPS). The resultant Janus droplets are highly monodisperse in structures and internal morphologies. Due to the affinity partitioning properties of ATPS, encapsulated ingredients can automatically partition into different compartments of the resultant Janus droplets. The use of biocompatible and cytocompatible ATPS also enables the encapsulation of enzymes and cells in the resultant droplets with their activity preserved at a relatively high level. image