Synthetic biology is the study and engineering of organisms with novel, unique functions. Specifically, bottom-up synthetic biology involves assembling complex cells or structures from simpler units. One such component of this field involves the production of artificial cells. By employing a bottom-up approach, researchers can investigate individual properties of the cell such as lipid membrane characteristics, specific biological pathways, and encapsulation phenomena.

Microfluidic methods enable the uniform generation of artificial cell precursors, otherwise known as Double Emulsions Droplets (DEDs). Although DEDs are versatile in both composition and application, they can be limited by their instability and susceptibility to rupture. This is observed by a reduction in DED concentration over time. Here we present a study for the optimization of the external aqueous phase resulting in the most stable and highest concentration of DEDs over a period of two weeks. By post-processing the DEDs in squeezing channels, the oil layer is thinned resulting in less depletion of the sample.