Department of Physics, São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, SP 15054-000, Brazil.
Department of Physics, North Dakota State University, Fargo North Dakota, ND 58108-6050, USA.
Molecules. 2020 Aug 22;25(17):3824. doi: 10.3390/molecules25173824.
Interactions between charges and dipoles inside a lipid membrane are partially screened. The screening arises both from the polarization of water and from the structure of the electric double layer formed by the salt ions outside the membrane. Assuming that the membrane can be represented as a dielectric slab of low dielectric constant sandwiched by an aqueous solution containing mobile ions, a theoretical model is developed to quantify the strength of electrostatic interactions inside a lipid membrane that is valid in the linear limit of Poisson-Boltzmann theory. We determine the electrostatic potential produced by a single point charge that resides inside the slab and from that calculate charge-charge and dipole-dipole interactions as a function of separation. Our approach yields integral representations for these interactions that can easily be evaluated numerically for any choice of parameters and be further simplified in limiting cases.
脂质膜内部的电荷和偶极子相互作用部分被屏蔽。这种屏蔽既来自于水分子的极化，也来自于膜外盐离子形成的双电层结构。假设膜可以表示为一个低介电常数的介电片，夹在含有可移动离子的水溶液中，我们开发了一个理论模型来量化脂质膜内部静电相互作用的强度，该模型在泊松-玻尔兹曼理论的线性极限下是有效的。我们确定了位于片内的单个点电荷产生的静电势，并由此计算出电荷-电荷和偶极子-偶极子相互作用作为分离的函数。我们的方法为这些相互作用提供了积分表示，可以很容易地针对任何参数选择进行数值评估，并在极限情况下进一步简化。
