Asymmetric Lipid Membranes under Shear Flows: A Dissipative Particle Dynamics Study.

Linli He,Zhenguo Wang,Xianghong Wang,Yongyun Ji,Yanying Chen,Shiben Li

doi:10.3390/membranes11090655

Abstract

We investigate the phase behavior of the asymmetric lipid membranes under shear flows, using the dissipative particle dynamics simulation. Two cases, the weak and strong shear flows, are considered for the asymmetric lipid microstructures. Three typical asymmetric structures, the membranes, tubes, and vesicle, are included in the phase diagrams, where the effect of two different types of lipid chain length on the formation of asymmetric membranes is evaluated. The dynamic processes are demonstrated for the asymmetric membranes by calculating the average radius of gyration and shape factor. The result indicates that different shear flows will affect the shape of the second type of lipid molecules; the shape of the first type of lipid molecules is more stable than that of the second type of lipid molecules. The mechanical properties are investigated for the asymmetric membranes by analyzing the interface tension. The results reveal an absolute pressure at the junctions of different types of particles under the weak shear flow; the other positions are almost in a state of no pressure; there is almost no pressure inside the asymmetric lipid membrane structure under the strong shear flow. The findings will help us to understand the potential applications of asymmetric lipid microstructures in the biological and medical fields.

Highlights

A lipid molecule usually consists of one head chain and one or two more tail chains, which is an indispensable part of the human body and a vital component of various products, such as food, cosmetics, and medicines [1–3]
We analyze the shear-induced assembly of asymmetric lipid membranes by a dissipative particle dynamics (DPD) simulation in aqueous solutions based on the CG model under the weak and strong shear flows
Some tubes and vesicles are induced into membranes with γ = 0.073, while with γ = 0.168, only membranes and tubes exist in the phase diagram

Summary

Introduction

A lipid molecule usually consists of one head chain and one or two more tail chains, which is an indispensable part of the human body and a vital component of various products, such as food, cosmetics, and medicines [1–3]. Due to the amphipathicity of head and tail chains in the aqueous solutions, lipid molecules can self-assemble into many different structures, such as the membrane, tube, vesicle, and a series of continuous structures. Among these lipid structures, the membrane, i.e., the lamellar structure, as the boundary between two diverse environments, is the main structure of the cell membranes, which arises wide concern [4]. Daniel et al have researched a molecular organization and complex formation of FABT in DPPC multibilayers [6]. On the basis of the interpretation of Fourier transform infrared spectra, Dariusz Kluczyk et al have analyzed the molecular organization of two compounds, that is, C1 and C7, in multilayers formed from DPPC and the 1,3,4-thiadiazoles [7]. The asymmetry and shear flows should be considered for the lipid membranes, which is beneficial to explore the mechanism of self-assembly and potential biological applications of asymmetric lipid microstructures

Methods

Results

Conclusion