Stankowski S
Biocenter of the University, Basel, Switzerland.
Biophys J. 1991 Aug;60(2):341-51. doi: 10.1016/S0006-3495(91)82059-8.
Traditionally, Gouy-Chapman theory has been used to calculate the distribution of ions in the diffuse layer next to a charged surface. In recent years, the same theory has found application to adsorption (incorporation, partitioning) of charged peptides, hormones, or drugs at the membrane-water interface. Empirically it has been found that an effective charge, smaller than the physical charge, must often be used in the Gouy-Chapman formula. In addition, the large size of these molecules can be expected to influence their adsorption isotherms. To improve evaluation techniques for such experiments, comparatively simple extensions of the standard Gouy-Chapman formalism have been studied which are based on a discrete charge virial expansion. The model allows for the mobility of charged groups at the interface. It accounts for finite size of the adsorbed macromolecules and for discrete charge effects arising from pair interactions in the interface plane. In contrast to previous discrete charge treatments this model nearly coincides with the Gouy-Chapman formalism in the case where the adsorbing molecules are univalent. Large discrepancies are found for multivalent molecules. This could explain the reduced effective charges needed in the standard Gouy-Chapman treatment. The reduction factor can be predicted. The model is mainly limited to low surface coverage, typical for the adsorption studies in question.
传统上， Gouy-Chapman理论一直用于计算带电表面附近扩散层中离子的分布。近年来，同一理论已被应用于带电肽、激素或药物在膜 - 水界面的吸附（掺入、分配）。根据经验发现，在Gouy-Chapman公式中，通常必须使用比物理电荷小的有效电荷。此外，这些分子的大尺寸预计会影响它们的吸附等温线。为了改进此类实验的评估技术，已经研究了基于离散电荷维里展开的标准Gouy-Chapman形式主义的相对简单的扩展。该模型考虑了界面处带电基团的迁移率。它考虑了吸附大分子的有限尺寸以及界面平面中对相互作用产生的离散电荷效应。与以前的离散电荷处理不同，在吸附分子为单价的情况下，该模型几乎与Gouy-Chapman形式主义一致。对于多价分子，发现有很大差异。这可以解释标准Gouy-Chapman处理中所需的有效电荷减少的原因。可以预测减少因子。该模型主要限于低表面覆盖率，这是所讨论的吸附研究的典型情况。
