The Effects Of Surfactant On Lipid Membrane Penetrability By Molecular Dynamics Simulations

One of the major challenges in nanomedicine is to improve nanoparticle cell selectivity and adhesion efficiency through designing functionalized nanoparticles of controlled sizes, shapes, and materials composition, the functional process of nanomedicine in organism can divide as three parts: bonding, penetrating and drug release. In the process of nanomedicine’s penetration, some ligands on the out surface of nanomedicine tend to stay in lipid membrane because of adsorption energy, therefore, they will affect the penetration characteristics of lipid membrane and the penetration process of nanomedicine. With the fast development of computer technology nowadays, a great deal of effects have been brought and provoked. For a long time, scientists are trying to find an effective method to tackle some serious diseases that are too complex to treat and recovery, such as cancer,Aids etc. The emerge of nanomedicine gives majority of choices and indications to the whole biological field. Also, the pretty advanced computer technology has been used to research, design and develop new medicines.Based on Molecular Dynamics Simulation principles, this thesis employed LAMMPS and Material Studio software to proceed the research of effects of surfactants on penetrability of lipid membrane. On the initial stage of modeling, we used Dissipative Particle Dynamics and coarse-grained modeling techniques to enhance the efficiency and the computational time. The whole molecular dynamics simulation system contains three parts: the fluid flow(coarse-grained water beads), lipid membrane and surfactant(ligand), accordingly, the fluid flow is consisted by lots of coarse-grain beads. The harmonic and Dissipative Particle Dynamics force fields are used in the simulation according to the specific requirements and conditions.In this paper, we intend to research the effects of surfactants on penetrability of lipid membrane, using molecular dynamics simulation. Coarse-grained simulation system is built and a variety of surfactants are employed. Further, we optimize the simulation system and get a stable energy condition. At the same time, we calculate MSD and concentration profile of coarse-grained water molecules. At the same time, during the simulation process, we observe the effects of different proportion of surfactants on the structure of lipid membrane. We found that the more surfactants will promote the penetration ability of lipid membrane, further, with the increase of surfactant, lipid membrane behaves like surfactant functions, which is more unstable and changeable. As a result, this situation will affect the penetrating process of nanomedicine. This is profound and significant for the design and manufacture of nanomedicines.