Kumari P, Pillai V V S, Gobbo D, Ballone P, Benedetto A
School of Physics, University College, Dublin, Ireland and Conway Institute for Biomolecular and Biomedical Research, University College, Dublin, Ireland.
Computational and Chemical Biology, Fondazione Istituto Italiano di Tecnologia, Genova, Italy.
Phys Chem Chem Phys. 2021 Jan 21;23(2):944-959. doi: 10.1039/d0cp04959j.
The nanostructure in water solutions of three organic ionic liquids relevant for biological applications has been studied by molecular dynamics simulations based on empirical force fields. The three compounds consisted of two different triethylammonium salts, known to affect the fibrillation kinetics of Aβ peptides, and a phosphonium dication, which has been shown to possess a marked bactericidal activity. The structure of solutions spanning a wide concentration range (from 25 to 75 wt%) has been analysed by computing several combinations of partial structure factors, measuring the fluctuation of the ion and water distribution in space. At moderate salt concentration, the results reflect the formation in water of salt-rich domains of nanometric size. With salt concentration increasing beyond 50 wt%, the system enters the so-called water-in-salt regime, in which the aggregation properties of water become relevant, giving origin to water-rich domains in the nearly uniform salt environment. The persistence over a wide concentration range of nearly integer (∼6; ∼4) water-ion coordination numbers suggests the formation of stoichiometric liquid ionic hydrates.
通过基于经验力场的分子动力学模拟，研究了三种与生物应用相关的有机离子液体水溶液中的纳米结构。这三种化合物由两种不同的三乙铵盐组成，已知它们会影响Aβ肽的纤维化动力学，还有一种磷鎓双阳离子，已证明其具有显著的杀菌活性。通过计算部分结构因子的几种组合，测量离子和水在空间中的分布波动，分析了跨越较宽浓度范围（从25 wt%到75 wt%）的溶液结构。在中等盐浓度下，结果反映出在水中形成了纳米尺寸的富盐区域。当盐浓度增加到超过50 wt%时，系统进入所谓的盐包水状态，其中水的聚集性质变得重要，在几乎均匀的盐环境中产生富水区域。在较宽浓度范围内接近整数（约6；约4）的水 - 离子配位数的持续存在表明形成了化学计量的液体离子水合物。
