爆炸波对生物膜微观创伤的分子动力学分析

Molecular Dynamics Analysis of Microscopic Injury in Biological Membrane by Blast Wave

爆炸冲击波作用到人体胸部时,肺部会出现肺出血及肺水肿等症状,这是人体爆炸创伤的主要原因,深入研究很有必要.为了更好地理解爆炸创伤的机理,应研究冲击波与微观组织作用的力学过程,但具有一定的难度.本文从基本的生物膜做起,运用分子动力学研究冲击波对DPPC膜造成的损伤,通过停止活塞来控制冲击波的冲量,观察冲击过程中膜的恢复情况.通过观察不同冲量下冲击波经过膜后磷脂分子及其周围水分子分布,发现随着冲量增大,膜越来越无序混乱,褶皱更严重,疏水区水分子越来越多.将膜冲击过程划为3个阶段,分别为冲击阶段、恢复阶段和后效阶段.发现当冲量大于153 m Pa·s时,在冲击过程中没有观察到膜的损伤恢复.

Blast wave can cause injury to human lungs,eardrums,gastrointestinal tract,brain and other organs.The lungs,eardrums,and air-containing gastrointestinal tract are more likely to cause damage.The study of explosive injury mechanism is of great significance to the treatment and protection of explosive injury and the design of explosive devices.Pulmonary hemorrhage,pulmonary edema,and air embolism are the main causes of explosive trauma death.Regarding the problem of explosive lung injury,the existing research in the macro aspect mainly involves several aspects such as explosion wave and animal experiments,mechanical models and numerical finite element simulation.In order to better understand the mechanism of blast injury,the mechanical process of the impact of the shock wave and microstructure should be studied.In this paper,the damage of DPPC(dipalmitoyl phosphatidyl choline)membrane caused by shock wave was studied by using all-atomic molecular dynamics.The impulse of shock wave was controlled by stopping the piston,and the critical impulse of membrane damage caused by shock wave was discussed.We observed the distribution of phospholipid molecules and surrounding water molecules after the shock wave passed through the membrane under different impulses.It was found that as the impulse increased,the membrane became more and more disordered,the folds were more severe,and more and more water molecules in the hydrophobic area.The membrane impact process was divided into three stages,namely the impact stage,recovery stage and after-effect stage.When the impulse is greater than153 mPa·s,the damage of the membrane is not recovered during the impact.