Beneficial effect of the physical properties of cholesteric liquid crystals on the membrane of biological cells

Abstract

The physical properties of cholesterol (cholesteric liquid crystal) ensure the correct packaging of the phospholipid part of the membrane, which is necessary for its normal operation, affecting on the mobility of the fatty acid tails of membrane lipids: if the membrane is too rigid and there is a danger of "freezing" fatty acid chains, cholesterol causes them to liquefy, since chains in his presence become more mobile; if the membrane is too “liquid”, then cholesterol thickens it. A number of authors explain this sealing effect of cholesteric liquid crystal (cholesterol) by the fact that the cholesteric liquid crystal (cholesterol), containing in the biological membrane, due to its physical properties, reduces the slope of hydrocarbon phospholipid tails, located not perpendicular to the membrane plane, but at a certain angle. The physical properties of cholesterol thus increase the elasticity and mechanical strength of the bilayer of bipolar phospholipids of membrane cell, due to which the membrane can change its shape in response to the force applied to it. The physical properties of cholesterol control the permeability of the bipolar phospholipids bilayer of the biological cell membrane. At temperatures above the phase transition of phospholipids, cholesterol has a condensing effect (a decrease of the area, occupied by a phospholipid molecule), reduces the rate of diffusion of phospholipids in the bilayer, and reduces the permeability of the bipolar phospholipid bilayer of membrane cell by water molecules and ions. At temperatures below the phase transition of phospholipids, cholesterol increases the area, occupied by the phospholipid molecule, increases the rate of diffusion of phospholipids in the bilayer, and increases the permeability of the bipolar phospholipid bilayer of membrane cell by water molecules and ions. The article presents a theoretical description of the beneficial influence of the physical properties of a cholesteric liquid crystal (cholesterol) on the membrane of biological cells, which plays a vital role in biological cells. It will be shown how the physical properties of cholesterol or cholesteric liquid crystal, located in the membrane of a biological cell, placed in a solution of a negatively charged catholyte, sharply increase the permeability of the bipolar phospholipid bilayer of the biological membrane cell by water molecules and ions through the cholesteric liquid crystal or cholesterol into the inside of the biological cell due to in this case, an increase of the positive electrostatic potential of the outer layer of the bipolar phospholipid bilayer, which contributes to the adoption by a cholesteric liquid crystal or cholesterol of a configuration with open gaps in relation to the environment (catholyte solution of nutrient media) between its monolayers, and thereby accelerating the exchange processes between the cell and its environment, contributing to its rapid reproduction. It will also be shown that the physical properties of cholesterol or cholesteric liquid crystal, located in the membrane of a cancer cell, placed in an aqueous solution of a positively charged anolyte, prevent the penetration of water molecules and ions through cholesterol or cholesteric liquid crystal into the inside of the cancer cell by reducing the positive electrostatic potential of the external layer of the bipolar phospholipid bilayer to zero, which contributes to o the adoption by a cholesteric liquid crystal or cholesterol of a configuration with close gaps in relation to the environment (anolyte solution) between the monolayers of cholesteric liquid crystal or cholesterol in the bipolar phospholipid bilayer of the cancer cell membrane, which stops the exchange of the cancer cell with the environment, leading to its death.