[Effect of phase transition on electric capacitance of plane lipid membranes].

Effect of lipid phase transition on electric capacitance of plane lipid membranes was studied. For this purpose the capacitance of the membranes formed from solutions of saturated synthetic phospholipids in different solvent systems were measured at different temperatures. It was found that the capacitance of the membranes formed from phospholipid solution in dioxane having practically no solvent decreased at phase transition from liquid crystal state to gel.

[Effect of pH on the properties of planar lipid bilayers of cholesterol and alpha-monolaurine].

It is discovered that pH of liquid electrolyte influences the structure, stability and conductance of bilayer lipid membranes (BLM) formed from cholesterol-alpha-monolaurine mixture in n-octane. The most stable BLM are formed at cholesterol-alpha-monolaurine weight ratio 1:1, BLM specific resistance being maximal and their thickness minimal (2.9 nm).

[Properties of bilayer lipid membranes formed from cholesterol and alkyltrimethylammonium bromides].

Flat bilayer lipid membranes (BLM) were obtained from cholesterol solution in n-octane in the presence of detergents of alkyltrimethyl ammonium bromides series in water medium. It has been shown that highly stable BLM are obtained only for the detergents of this series with the alkyl chain higher than C12. Changes in stability and electromechanical strength of the latter are conditioned by the peculiarities of stechiometric interaction between the molecules of cholesterol, detergent and solvent in the lipid bilayer.

[Stabilization of flat bilayer lipid membranes by cholesterol].

Cholesterol is found to produce a stabilizing effect on bilayer lipid membranes (BLM) from alpha-monoglycerides of fatty acids and n-octan. The greatest stabilization effect is observed for alpha-monoglycerides, in which the length of hydrocarbon radical coincides with the length of cholesterol molecule. The life time of BLM from alpha-monolaurin, cholesterol and n-octan is measured in hours, and the tension of electric damage of the membrane reaches 860 mV.