Development and validation of a dual filtration technique to control the size distribution of giant lipid vesicles

Abstract

A new purification technique is developed for obtaining the distribution of giant unilamellar vesicles (GUVs) within a specific range of sizes using dual filtration. The GUVs were prepared using the natural swelling method. For filtration, different combinations of polycarbonate membranes were utilized in filter holders. In this experiment, the combinations of membranes were selected with three pairs of pore sizes, such as, (i) 12 and 10 μm, (ii) 12 and 8 μm, and (iii) 10 and 8 μm. By these filtration arrangements, obtained GUVs size distributions were in the ranges of 6−26 μm, 5–38 μm, and 5–30 μm, respectively. The size distribution range for the dual filtration technique was found lower, the mode was smaller, and also the skewness became smaller (narrow size distribution) than for the single filtration technique. By continuing this process of purification for a second time, the GUVs size distribution became even narrower. After using an extra filtration with dual filtration, two different size distributions of GUVs were obtained at a time. This experimental observation suggests that different specific size distributions of GUVs can be obtained easily, even if GUVs are prepared by different other methods. Using this technique, the water-soluble fluorescent probe, calcein, has been removed from the suspension of GUVs successfully.