We employed scanning electrochemical microscope (SECM) with inverted open platinum electrode (IOPE), integrated with Langmuir bath, to investigate the impact of long-chain hydrocarbons on the permeability of membranes for O2. We show that oxygen permeability of membranes composed of long-chain fatty acids (C18 - stearic or C20 - arachidic) sharply decreases in response to increasing surface pressure in the range 20-45 mN/m. Addition of cholesterol to these membranes (up to 10%) inhibits the effect of surface pressure on the O2 transfer rate. Permeability of membranes composed of lipids with shorter chains (C16 and less) remains high regardless of lateral pressure. Physiological role of the detected phenomena is discussed in connection with O2 gas exchange through the membrane of erythrocytes in blood capillaries. We discuss formation of the elongated cell shape in the capillary, increase in the surface area of the cell membrane, reduction of surface tension in the membrane, reduction of the gap between the erythrocyte membrane and the walls of the capillary, movement of the cell along the capillary, the causes and speed of the cell return to its normal biconcave shape.
Dioxygen diffusion, long-chain hydrocarbons monolayers, surface pressure, cholesterol, SECM
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