Production of Giant Unilamellar Vesicles and Encapsulation of Nematic Lyotropic Liquid Crystals

We describe a modified microfluidic method for making Giant Unilamellar Vesicles (GUVs)viawater/octanol-lipid/water double emulsion droplets. At a high enough lipid concentration we show that thede-wetting of the octanol from these droplets occurs spontaneously (off-chip) without the need to useshear to aid the de-wetting process. The resultant mixture of octanol droplets and GUVs can beseparated by making use of the buoyancy of the octanol. A simpler microfluidic device and pumpsystem can be employed and, because of the higher flow-rates and much higher rate of formation ofthe double emulsion droplets (B1500 s 1compared to up toB75 s 1), it is easier to make largernumbers of GUVs and larger volumes of solution. Because of the potential for using GUVs thatincorporate lyotropic nematic liquid crystals in biosensors we have used this method to make GUVs thatincorporate the nematic phases of sunset yellow and disodium chromoglycate. However, the phasebehaviour of these lyotropic liquid crystals is quite sensitive to concentration and we found that there isan unexpected spread in the concentration of the contents of the GUVs obtained.