Tip Streaming of a Lipid-Stabilized Double Emulsion Generated in a Microfluidic Channel

Water/oil/water
(w/o/w) double emulsions (DEs) are multicompartment
structures which can be used in many technological applications and
in fundamental studies as models of cell like microreactors or templates
for other materials. Herein, we study the flow dynamics of water/oil/water
double emulsions generated in a microfluidic device and stabilized
with the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine
(DMPC). We show that by varying the concentration of lipids in the
oil phase (chloroform) or by modulating the viscosity of the aqueous
continuous phase, the double emulsions under flow exhibit a rich dynamic
behavior. An initial deformation of the double emulsions is followed
by tube extraction at the rear end, relative to the flow direction,
resulting in pinch off at the tube extremity by which small aqueous
compartments are released. These compartments are phospholipid vesicles
as deduced from fluorescence experiments. The overall process can
thus be of help to shed light on the mechanical aspects of phenomena
such as the budding and fusion in cell membranes.