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Study of cholesterol in tethered membrane using coarse grained molecular dynamics simulations Duan, Yan


This work presents a study of cholesterol's effects on archaebacterial cell membranes using coarse grain molecular dynamic simulations. As a major component in biological membranes, cholesterol is closely related to the dynamics of lipids and biomechanical properties of the membrane. A coarse grained molecular dynamics (CGMD) model is constructed to study the membrane properties. The CMGD model provides insights into the diffusion dynamics of lipids, membrane thickness, line tension, and surface tension as a function of cholesterol content. The CGMD simulation results are validated using experimental measurements from a tethered archaebacterial bilayer lipid membrane. The membrane is tethered to an inert gold bioelectronic interface, which allows the experimental measurements to be performed using standard laboratory equipments. A fractional order macroscopic model is introduced to link microscopic simulation results with macroscopic experimental measurements. To ensure the bioelectronic interface does not affect the membrane dynamics and biomechanics, it is shown that variations in the position dependent water density are negligible near the surface of the membrane. Furthermore, the Percus-Yevick equation is used to confirm that harsh repulsive forces play a negligible role in the long range dynamics of the water density profile.

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