Application of a Thermodynamic Model for Charged Interfaces to Lipid Membranes

We have previously [M. N. Kobrak, J. Phys.: Cond. Matt. 25 095006 (2013)] presented a thermodynamic model describing the relationship between the ionic strength of an electrolyte, the morphology of an interface with which it is in contact, and the distribution of ions within the system. We have shown that in some circumstances, the ionic strength of an electrolyte solution confined within a pore can be different from that of a macroscopic reservoir in which it is in contact. We apply the same model to electrolyte solutions enclosed by charged lipid bilayers, and show that the effect may be significant for small, unilamellar vesicles. However, the results also indicate that the effect will not be significant for biological systems in general.