标题： 溶剂动力学增强了膜脂的集体扩散 显示英文标题

标题： Solvent hydrodynamics enhances the collective diffusion of membrane lipids

摘要： 膜脂在数百纳米和纳秒范围内的集体运动对于细胞膜中脂质和蛋白质的亚微米复合物的形成是至关重要的。 这些动态很难通过实验进行研究，目前了解得还不够深入。 著名Saffman-Debrück（SD）理论的一个结论是，小于Saffman长度（微米）的脂质扰动不会受到周围溶剂流体动力学的影响。 我们使用分子动力学和具有隐式流体动力学的粗粒模型表明，这一结论并不正确。 膜与溶剂之间的流体动力学相互作用在所有尺度上显著增强了脂质的短时间集体扩散。 膜与溶剂在正常方向上的动量传递（SD理论未考虑这一点）沿着膜表面传播，导致脂质之间产生长程排斥力。 因此，脂质集体扩散系数与扰动波长成比例增加。 我们发现与准二维动力学中预测的异常扩散有定量一致性，这种现象在被限制在平面上但嵌入三维溶剂中的胶体中已被观察到。 显示英文摘要

摘要： The collective motion of membrane lipids over hundred of nanometers and nanoseconds is essential for the formation of submicron complexes of lipids and proteins in the cell membrane. These dynamics are difficult to access experimentally and are currently poorly understood. One of the conclusions of the celebrated Saffman-Debr\"uck (SD) theory is that lipid disturbances smaller than the Saffman length (microns) are not affected by the hydrodynamics of the embedding solvent. Using molecular dynamics and coarse-grained models with implicit hydrodynamics we show that this is not true. Hydrodynamic interactions between the membrane and the solvent strongly enhance the short-time collective diffusion of lipids at all scales. The momentum transferred between the membrane and the solvent in normal direction (not considered by the SD theory) propagates tangentially over the membrane inducing long-ranged repulsive forces amongst lipids. As a consequence the lipid collective diffusion coefficient increases proportionally to the disturbance wavelength. We find quantitative agreement with the predicted anomalous diffusion in quasi-two-dimensional dynamics, observed in colloids confined to a plane but embedded in 3D solvent.