[Effect of phase transition on electric capacitance of plane lipid membranes]. / Vliianie fazovogo perekhoda na élektricheskuiu emkost' ploskikh lipidnykh membran.

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. It can be explained by an increased membrane thickness during phase transition due to a change of conformation of phospholipid hydrocarbon chains. At the same time the capacitance of the membranes formed from phospholipid solution in normal hydrocarbons increased at the temperatures below the phase transition one. The latter results agree with the data of other authors. It is explained by the thinning of the membrane at the expense of solvent yield from the membrane phase to microlenses.

[Effect of pH on the properties of planar lipid bilayers of cholesterol and alpha-monolaurine]. / Vliianie pH na svoistva ploskikh bisloinykh lipidnykh membran iz kholesterina i alpha-monolaurina.

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). A sharp reduction of BLM stability is noted when pH is deviated in acidic or alkaline medium. The obtained data are discussed from the viewpoint of adsorbed charge influence on the structure of BLM formed of uncharged lipids.

[Properties of bilayer lipid membranes formed from cholesterol and alkyltrimethylammonium bromides]. / Svoistva bisloinykh lipidnykh membran, obrazovannykh iz kholesterina i alkiltrimetilammoniibromidov.

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]. / O stabilizatsii ploskikh bisloinykh lipidnykh membran kholesterinom.

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.