A new purification technique to obtain specific size distribution of giant lipid vesicles using dual filtration

Abstract

A new purification technique is developed for obtaining distribution of giant unilamellar vesicles (GUVs) within a specific range of sizes using dual filtration. The GUVs were prepared using well known natural swelling method. For filtration, different combinations of polycarbonate membranes were implemented in filter holders. In our experiment, the combinations of membranes were selected with corresponding pore sizes–(i) 12 and 10 μm, (ii) 12 and 8 μm, and (iii) 10 and 8 μm. By these filtration arrangements, obtained GUVs size distribution were in the ranges of 6−26 μm, 5–38 μm and 5–30 μm, respectively. In comparison, the size distribution range was much higher for single filtration technique, for example, 6−59 μm GUVs found for a membrane with 12 μm pores. Using this technique, the water-soluble fluorescent probe, calcein, can be removed from the suspension of GUVs successfully. The size distributions were analyzed with lognormal distribution. The skewness became smaller (narrow size distribution) when a dual filtration was used instead of single filtration. The mode of the size distribution obtained in dual filtration was also smaller to that of single filtration. 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 size specific distributions of GUVs can be obtained easily, even if GUVs are prepared by different other methods.

Effects of cholesterol on the size distribution and bending modulus of lipid vesicles

“…The standard deviation of the mean of the average size of GUVs was significantly small, which makes us confident to present the data. Similar approach was followed in our several recent papers [7,25,64,65]. Here, we presented only one independent experiment in each condition.…”

“…On the other hand, the ranges of the diameters of GUVs were 5.6 − 50.9 μm and 5.5-72.3 μm as shown in Figs 3A, 3B and 3C, 3D, respectively. The same technique was used in our recent papers to measure the similar range of size distribution of GUVs [7,25,64,65]. In addition, another group was able to measure the GUVs with diameters greater than 2 μm using the similar technique [77].…”

Measuring Encapsulation Efficiency in Cell-Mimicking Giant Unilamellar Vesicles

“…One might expect the throughput and yield of a bulk phase transfer and FACS workflow to be considerable and help maintain the facile nature of the method and maintain as low a barrier to entry as possible. Size-based passive filtering has been reported using membrane filtration as well as microfluidic systems with high recovery rates. − It may be possible to harness synthetic biology approaches to act as internal standards or to design a dynamic population of vesicles that post-synthetically develop programmatically toward homogeneous expression. A report by Nourian and Danelon provides an intriguing example of how this might be achieved using models of gene expression but also caution when implementing such approaches in vesicle-based systems since only a small fraction of bulk DNA is encapsulated in a transcribable manner …”

Emerging biomaterials for tumor immunotherapy

“…A rotary evaporator is adopted to remove solvents under reduced pressure and controlled temperature. The prepared liposomes are resolved in an organic phase after nitrogen purging, thereby increasing the drug encapsulation rate [ 237 , 238 ]. 4.…”