https://escholarship.org/content/qt0k0461m4/qt0k0461m4.pdf?t=oeiyiz

Lipid rafts reconstituted in model membranes.

https://www.cell.com/biophysj/pdf/S0006-3495(03)74726-2.pdf

Separation of liquid phases in giant vesicles of ternary mixtures of phospholipids and cholesterol.

Seeing spots: Complex phase behavior in simple membranes

There is considerable interest in preparing cell-sized giant unilamellar vesicles from natural or nonnatural amphiphiles because a giant vesicle membrane resembles the self-closed lipid matrix of the plasma membrane of all biological cells. Currently, giant vesicles are applied to investigate certain aspects of biomembranes. Examples include lateral lipid heterogeneities, membrane budding and fission, activities of reconstituted membrane proteins, or membrane permeabilization caused by added chemical compounds. One of the challenging applications of giant vesicles include gene expressions inside the vesicles with the ultimate goal of constructing a dynamic artificial cell-like system that is endowed with all those essential features of living cells that distinguish them from the nonliving form of matter. Although this goal still seems to be far away and currently difficult to reach, it is expected that progress in this and other fields of giant vesicle research strongly depend on whether reliable methods for the reproducible preparation of giant vesicles are available. The key concepts of currently known methods for preparing giant unilamellar vesicles are summarized, and advantages and disadvantages of the main methods are compared and critically discussed.

Giant Vesicles: Preparations and Applications

We have recently developed a minimal system for generating long tubular nanostructures that resemble tubes observed in vivo with biological membranes. Here, we studied membrane tube pulling in ternary mixtures of sphingomyelin, phosphatidylcholine and cholesterol. Two salient results emerged: the lipid composition is significantly different in the tubes and in the vesicles; tube fission is observed when phase separation is generated in the tubes. This shows that lipid sorting may depend critically on both membrane curvature and phase separation. Phase separation also appears to be important for membrane fission in tubes pulled out of giant liposomes or purified Golgi membranes.

/pdf/role-of-curvature-and-phase-transition-in-lipid-sorting-and-3gc4rwhept.pdf

Role of curvature and phase transition in lipid sorting and fission of membrane tubules

We suggest a method for preparation of large (∼ 15 ÷ 70 μm in diameter), unilamellar, fluctuating, isolated vesicles, allowing us to perform routine measurements of membrane bending elasticity modulus k c by image analysis of thermal fluctuations. The method is based on the effects of AC electric fields on the lipid swelling and liposome formation. We have observed a monotonous decrease of k c for egg phosphatidylcholine (EPC) vesicles from (0.66 ± 0.06) · 10−19 J for 1 day to (0.45 ± 0.05) · 10−19 J for 13 days after vesicle formation. The lipid mixture Chol/PC 37:63 mol/mol led to k c = (1.06 ± 0.15) · 10−19 J, and PE/PC 25:75 mol/mol — to (0.72 ± 0.06) · 10−19 J. — The mechanism of vesicle formation is discussed. It proved that the basic phenomenon is sequences of lateral fusions of smaller vesicles induced by the applied AC electric field.

F. Faucon

Papers

Preparation of giant vesicles by external AC electric fields. Kinetics and applications