Langmuir-Blodgett monolayers and multilayers of gramicidin A and lipids as membrane-mimetic models

Abstract

Monolayers and multilayers of Gramicidin A (channel-forming protein in biological membranes and its mixtures with methyl stearate and ethyl palmitate were studied in order to prepare mimetic membranes for the selective ion transport using Langmuir-Blodgett (LB) films. Monolayers of Gramicidin A were spread at different temperatures and on different subphases containing Na +, K + and Ca 2+ ions, and ions were investigated using FT-IR-ATR spectra of LB multilayers to detect conformational changes at the interface. The dependence of the values of molecular areas and the collapse pressure as a function of molar fractions of Gramicidin A in mixtures with methyl stearate and ethyl palmitate, proved that the components showed complete and ideal miscibility. The FT-IR-ATR spectra of LB monolayers and multilayers of these mixtures were also reported.