Division of Physical Chemistry, Department of Chemistry , Lund University , SE-221 00 Lund , Sweden.
Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation , Forschungszentrum Jülich , D-52425 Jülich , Germany.
J Phys Chem B. 2018 Dec 27;122(51):12396-12402. doi: 10.1021/acs.jpcb.8b07901. Epub 2018 Dec 13.
The effect of a nonspherical particle shape on the dynamics in crowded solutions presents a significant challenge for a comprehensive understanding of interaction and structural relaxation in biological and soft matter. We report that small deviations from a spherical shape induce a nonmonotonic contribution to the crowding effect on the short-time cage diffusion compared with spherical systems, using molecular dynamics simulations with mesoscale hydrodynamics of a multiparticle collision dynamics fluid in semidilute systems with volume fractions smaller than 0.35. We show that the nonmonotonic effect due to anisotropy is caused by the combination of a reduced relative mobility over the entire concentration range and a looser and less homogeneous cage packing of nonspherical particles. Our finding stresses that nonsphericity induces new complexity, which cannot be accounted for in effective sphere models, and is of great interest in applications such as formulations as well as for the fundamental understanding of soft matter in general and crowding effects in living cells in particular.
非球形颗粒形状对拥挤溶液中动力学的影响，对全面理解生物和软物质中的相互作用和结构弛豫提出了重大挑战。我们报告说，与球形系统相比，即使是微小的偏离球形，也会导致短时间笼扩散的拥挤效应呈非单调贡献，这是使用介观流体动力学的分子动力学模拟，模拟多粒子碰撞动力学流体在半稀系统中的体积分数小于 0.35。我们表明，由于各向异性引起的非单调效应是由整个浓度范围内相对迁移率降低以及非球形颗粒的笼状包装更松散和更不均匀共同引起的。我们的发现强调了非球形引起的新复杂性，这在有效球体模型中无法得到解释，并且在制剂等应用中以及一般软物质特别是活细胞拥挤效应的基础理解中都具有重要意义。
