Single-step Microfluidic Production of W/O/W Double Emulsions As Templates for Β-Carotene-loaded Giant Liposomes Formation

We demonstrated the microfluidic production of W/O/W double emulsion droplets aiming formation of beta-carotene-incorporated giant liposomes for food and/or pharmaceutical applications. For this purpose, glass-capillary microfluidic devices were fabricated to create a truly three-dimensional flow aiming production of giant unilamellar liposomes by solvent evaporation process after W/O/W double emulsion droplet templates formation. A great challenge of microfluidic production of monodisperse and stable W/O/W double emulsion templates for this proposal is the replacement of organic solvents potentially toxic for phospholipids dissolution. Besides, the high cost of several semi-synthetic phospholipids commonly used for giant liposome formation remains as a major technological challenge to be overcome. Thus, beta-carotene-incorporated giant liposomes were generated using biocompatible solvents with low toxic potential (ethyl acetate and pentane) and non-purified soybean lecithin - a food-grade phospholipid mixture with low cost - by dewetting and evaporation of the solvents forming the oily intermediate phase of W/O/W double emulsion droplet templates. Our results showed monodisperse beta-carotene-loaded giant liposomes with diameter ranging between 100 mu m and 180 mu m and a stability of approximately 7 days. In this way, a single-step microfluidic process with highly accurate control of size distribution was developed. This microfluidic process proposed is potentially useful for a broad range of applications in protection and delivery of active compounds.