Ethanol and methanol induced changes in phospholipid monolayer

The main components of cell membranes are phospholipids and proteins. The aim of our study was to examine structural changes of dipalmitoyl-phosphatidylcholine (DPPC) monolayer as a simple model system of a cell membrane in different environments. Pure water, ethanol and methanol solutions were used as subphases of Langmuir films as a membrane models. For detection of changes in charge states of the molecules as well as relation with structural and conformational changes, a contactless method Maxwell’s displacement currents (MDC) was used. Behaviour of DPPC molecules on two different subphases is substantialy different. In DPPC monolayer on the subphase of methanol–water, a gradual absorption (incorporation, penetration) of methanol molecules into the layer can appear. In DPPC monolayer on the subphase of ethanol– water adsorption of ethanol molecules on the layer can be observed. The membrane permeability might change. At both subphases (ethanol–water and methanol–water) the elasticity modulus of the monolayer decreases leading to the loss of membrane elasticity