Microfluidic production of liposomes through liquid-liquid phase separation in ternary droplets

Liposomes,the self-assembled phospholipid vesicles,have been extensively used in various fields such as artificial cells,drug delivery systems,biosensors and cosmetics.However,current microfluidic routes to liposomes mostly rely on water-in-oil-in-water double emulsion droplets as templates,and require complex fabrication of microfluidic devices,and tedious manipulation of multiphase fluids.Here we present a simple microfluidic approach to preparing monodisperse liposomes from oil-in-water droplets.For demonstration,we used butyl acetate-water-ethanol ternary mixtures as inner phase and an aqueous solution of surfactants as outer phase to make oil-in-water droplets,which can evolve into water-in-oil-in-water double emulsion droplets by liquid-liquid phase separation of ternary mixtures.Subsequently,the resultant water-in-oil-in-water droplets underwent a dewetting transition to form separated monodisperse liposomes and residual oil droplets,with the assistance of surfactants.The method is simple,does not require complex microfluidic devices and tedious manipulation,and provides a new platform for controllable preparation of liposomes.