Effects of modified external conditions on the shape of phospholipid vesicles

Phospholipid bilayer is the basic constituent part of cell membranes. Phospholipids are amphiphilic molecules, which spontaneously form a bilayer in an aqueous medium. If the bilayer closes upon itself, a phospholipid vesicle is formed. The shape of flaccid vesicles and cells without internal structure depends on the elastic properties and environmental factors. We will theoretically describe the shape with derived equations, devised by a minimisation of thermodynamic potential. The response of vesicles and cells on modified environmental conditions will be observed with an optical microscope. We will try to investigate the conditions leading to transitions between different classes of shapes and to explain the dynamics of the process. The membrane properties will be studied via shape changes of closed phospholipid membranes depending on strength and frequency of applied electric field. Connecting the theoretical calculations with experiments, we will evaluate the nature of interactions between phospholipid membranes and environmental factors and determine the elastic properties of membranes.