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

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.

Conical Nanotubes Synthesized by Atomic Layer Deposition of Al2O3, TiO2, and SiO2 in Etched Ion-Track Nanochannels

Etched ion-track polycarbonate membranes with conical nanochannels of aspect ratios of ~3000 are coated with Al2O3, TiO2, and SiO2 thin films of thicknesses between 10 and 20 nm by atomic layer deposition (ALD). By combining ion-track technology and ALD, the fabrication of two kinds of functional structures with customized surfaces is presented: (i) arrays of free-standing conical nanotubes with controlled geometry and wall thickness, interesting for, e.g., drug delivery and surface wettability regulation, and (ii) single nanochannel membranes with inorganic surfaces and adjustable isoelectric points for nanofluidic applications.

Nerve influence on the metabolism of type I and type II diabetic corneal stroma: an in vitro study

Corneal innervation plays a major role in the pathobiology of diabetic corneal disease. However, innervation impact has mainly been investigated in the context of diabetic epitheliopathy and wound healing. Further studies are warranted in the corneal stroma-nerve interactions. This study unravels the nerve influence on corneal stroma metabolism. Corneal stromal cells were isolated from healthy (HCFs) and diabetes mellitus (Type1DM and Type2 DM) donors. Cells were cultured on polycarbonate membranes, stimulated by stable Vitamin C, and stroma-only and stroma-nerve co-cultures were investigated for metabolic alterations. Innervated compared to stroma-only constructs exhibited significant alterations in pyrimidine, glycerol phosphate shuttle, electron transport chain and glycolysis. The most highly altered metabolites between healthy and T1DMs innervated were phosphatidylethanolamine biosynthesis, and pyrimidine, methionine, aspartate metabolism. Healthy and T2DMs main pathways included aspartate, glycerol phosphate shuttle, electron transport chain, and gluconeogenesis. The metabolic impact on T1DMs and T2DMs was pyrimidine, purine, aspartate, and methionine. Interestingly, the glucose-6-phosphate and oxaloacetate was higher in T2DMs compared to T1DMs. Our in vitro co-culture model allows the examination of key metabolic pathways corresponding to corneal innervation in the diabetic stroma. These novel findings can pave the way for future studies to fully understand the metabolic distinctions in the diabetic cornea.

An Investigation Into The Fouling Phenomena Of Polycarbonate Membranes Used In The Treatment Of Latex Paint Wastewater

The treatment of latex paint wastewater with ultrafiltration allows for the reuse of the filtrate as process water or for cleaning purposes, as well as the potential for reclamation of the valuable paint solids. In this study, the utilization of polycarbonate membranes for the ultrafiltration of dilute latex dispersions was evaluated. Hydrophilic, flat sheet ultrafiltration membranes with a mean pore size of 0.1 μm were used. All filtration experiments were conducted under constant pressure operation, in a circular, centre-fed, cross-flow filtration cell. The effect of feed flow rate was investigated, and the steady-state permeate flux achieved showed an increase of 294% between 1.0 and 3.0 L/min. Increasing the operating pressure also resulted in an increased permeate flux, with a 320% increase from 1.5 to 5.5 psi. Also considered was the effect of the feed solid concentration on the permeate flux. When compared to the clean water flux (0% solids) of 5.5×10- Surfactant-enhanced ultrafiltration was also studied, with concentrations ranging from 25% to 200% of the literature values of the surfactant's critical micelle concentration (CMC) in pure water. The addition of an anionic surfactant, sodium dodecyl sulphate (SDS), reduced the effectiveness of the filtration. However, the addition of a cationic surfactant, cetyl trimethylammonium bromide (CTAB), increased the permeate flux of the latex dispersion up to 130% when twice its CMC was used, with evidence of a reduction in the effect of fouling of the membranes. This may be due to repelling interactions between the surface of the membrane and the surface of the formed micelles, as well as a reduced cake resistance due to the larger particle size of the constituents forming a less dense cake layer.

An Investigation Into The Fouling Phenomena Of Polycarbonate Membranes Used In The Treatment Of Latex Paint Wastewater

The treatment of latex paint wastewater with ultrafiltration allows for the reuse of the filtrate as process water or for cleaning purposes, as well as the potential for reclamation of the valuable paint solids. In this study, the utilization of polycarbonate membranes for the ultrafiltration of dilute latex dispersions was evaluated. Hydrophilic, flat sheet ultrafiltration membranes with a mean pore size of 0.1 μm were used. All filtration experiments were conducted under constant pressure operation, in a circular, centre-fed, cross-flow filtration cell. The effect of feed flow rate was investigated, and the steady-state permeate flux achieved showed an increase of 294% between 1.0 and 3.0 L/min. Increasing the operating pressure also resulted in an increased permeate flux, with a 320% increase from 1.5 to 5.5 psi. Also considered was the effect of the feed solid concentration on the permeate flux. When compared to the clean water flux (0% solids) of 5.5×10- Surfactant-enhanced ultrafiltration was also studied, with concentrations ranging from 25% to 200% of the literature values of the surfactant's critical micelle concentration (CMC) in pure water. The addition of an anionic surfactant, sodium dodecyl sulphate (SDS), reduced the effectiveness of the filtration. However, the addition of a cationic surfactant, cetyl trimethylammonium bromide (CTAB), increased the permeate flux of the latex dispersion up to 130% when twice its CMC was used, with evidence of a reduction in the effect of fouling of the membranes. This may be due to repelling interactions between the surface of the membrane and the surface of the formed micelles, as well as a reduced cake resistance due to the larger particle size of the constituents forming a less dense cake layer.

Ion track etching of polycarbonate membranes monitored by in situ small angle X-ray scattering

In situ small angle X-ray scattering (SAXS) measurements of ion track etching of polycarbonate foils are used to directly monitor the selective dissolution of ion tracks with high precision, including...

A facile template-assisted electrodeposition approach to porous Cu/Cu2O nanowires

A novel dual-template assisted electrodeposition method to fabricate Cu/Cu2O porous nanowires (PNs) using polymeric micelles as a soft template and polycarbonate membranes as a hard template is reported.