Effects of Triton X-100 on sonicated lecithin vesicles

Abstract

The effect of Triton X-100 on small unilamellar lecithin vesicles has been studied by means of quasi-elastic light scattering and cryogenic transmission electron microscopy. Low concentrations of Triton have little effect on the vesicle size, and very high concentrations give rise to the formation of mixed micelles. Addition of intermediate concentrations of surfactant results in the formation of very large vesicles with radii of up to 1000 A. The two methods give aggregate sizes in good agreement. Time-resolved cryo-TEM experiments showed that the time for the formation of the large vesicles is about 2 min. The use of a controlled environment vitrification system (CEVS) for the cryo-TEM sample preparation made it possible to visualize the aggregates formed without introducing artifacts due to changes in temperature or saturation.

Liposome Solubilization Induced by Surfactant Molecules in a Microchip

“…Such a growth of the liposome by the addition of surfactants has been reported in the low-concentration stage in the three stage model. 24,29,30 The difference of our observation is that the size growth occurs transiently, even in the high concentration stage in the model. In the dynamic processes, surfactants are taken up in the membrane until the threshold of the emission of mixed micelles, and then they are emitted.…”

“…An open vesicle that has large pores sufficient to pour out an inside liposome is confirmed by the observation using cryo-TEM. 21,29 Complicated behaviors of multilamellar liposomes due to these multilamellarity were reported recently.…”

“…In the dynamic processes, surfactants are taken up in the membrane until the threshold of the emission of mixed micelles, and then they are emitted. Since Cocera et al and Edwards et al reported that the emissions of mixed micelles take place in a few seconds, 24,29 the incorporation of the surfactant molecules into the membrane would be regarded as the rate-limiting step.…”

Modulation of Plasma Membrane Ca2+-ATPase by Neutral Phospholipids

“…It has been demonstrated that, after a micelle-vesicle transition, there might be a coexistence of bicelles with vesicles (53,54). In our system, PMCA may be inserted in a vesicle with its catalytic site facing either the luminal side or the solution.…”

Anomalous Solubilization Behavior of Dimyristoylphosphatidyl-choline Liposomes Induced by Sodium Dodecyl Sulfate Micelles

“…These processes have been studied using methods including microscopy, 5 UV/Vis spectroscopy, [6][7][8] dynamic light scattering, 9,10 and cryo-TEM. [11][12][13] Many studies have been made on the dependence of solubilization on the surfactant and lipid concentrations; it is well understood that this occurs in an equilibrium state. [14][15][16] At present, the three-stage model is generally accepted, where the ratio of the surfactants in the membrane determines the equilibrium condition of the phospholipids.…”