Departamento de Fisica Aplicada and Instituto Carlos I de Fisica Teorica y Computacional, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
Department of Chemical and Process Engineering, University of Strathclyde, Glasgow G1 1XJ, UK.
Colloids Surf B Biointerfaces. 2019 Jun 1;178:525-529. doi: 10.1016/j.colsurfb.2019.02.010. Epub 2019 Feb 20.
This work examines the influence of the charge distribution of trivalent cations on their interaction with soft anionic particles, using a combination of experimental measurements and theoretical modelling. In particular, we perform electrophoresis measurements to determine the zeta-potential of anionic liposomes in the presence of spermidine and lanthanum cations. We work in a range of electrolyte concentration where a reversal in the electrophoretic mobility of the liposomes is expected; however, unlike the case of lanthanum cations, spermidine does not induce mobility reversal of liposomes. As a result, the charge distribution within the counterion appears to be a key factor. This conclusion is supported by a theory that accounts for intra-ionic correlations, which has previously been successfully used to describe the colloidal electric double layer. It allows us to model spermidine as rod-like ions and lanthanum cations as point-like ions in order to test the importance of the ionic geometry in the interactions with soft particles such as lipid vesicles.
这项工作研究了三价阳离子的电荷分布对它们与软阴离子粒子相互作用的影响，采用了实验测量和理论建模相结合的方法。具体来说，我们进行电泳测量来确定在 spermidine 和镧阳离子存在下阴离子脂质体的 ζ 电位。我们在一系列电解质浓度下进行工作，预计脂质体的电泳迁移率会发生反转；然而，与镧阳离子的情况不同，spermidine 不会引起脂质体的迁移率反转。因此，反离子内的电荷分布似乎是一个关键因素。这一结论得到了一种理论的支持，该理论考虑了离子内相关性，该理论此前已成功用于描述胶体电动双层。它允许我们将 spermidine 建模为棒状离子，将镧阳离子建模为点状离子，以测试离子几何形状在与脂质体等软粒子相互作用中的重要性。
