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We have measured compression diagrams for monolayers composed of charged and neutral phospholipids in the pres- nce of various positively charged ions and polypeptides. The hape of diagrams and electrostatic effects was analyzed by the empirical model that represents lipid molecules as an in- ompressible kernel with a soft shell. We show that in the region of its liquid expanded state (LE) the measured Volta potential linearly depends on the lipid density, which corre- ponds to the effective value of the dipole moment according to Helmholtz relation. Such linearity chmkbremains inde- pendent of the pH solution, while a slope of curves chmkb- decreases markedly in the presence of polypeptideschmkb. We attribute this effect to the overpowering contribution of water molecules to the Volta potential in comparison to the surface charge changes. That is why the alteration in hy- dration of lipid head groups leads to the major changes in the dipole moment. A small, but noticeable deviation from inearity in the LE region was detected in the presence of chlorpromazine and polyarginine because of their insertion nto the monolayer. A quantitative description of diagrams was made by the previously developed model, which takes nto account the inhomogeneity of the polymer adsorption ayer. The study was supported by RFBR grant 19-04-00242.
№ | Имя | Описание | Имя файла | Размер | Добавлен |
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1. | программа конференции | 2021_Article_13thEBSACongressJuly24282021Vi.pdf | 3,4 МБ | 17 января 2022 [rodion.molotkovskiy] |