D. POPESCU*,*** , A.G. POPESCU**, B. AMUZESCU ***, ECATERINA MĂRIEŞ ***

*Department of Mathematical Modelling in Life Sciences, Institute of Mathematical Statistics and Applied Mathematics, Romanian Academy of Science, 13, Calea 13 Septembrie, Bucharest 050911, Romania
**Department of Computer Sciences, IT CORE SRL, 10, Garoafei St, Bucharest 051235, Romania
***Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, 91–95, Splaiul Independenţei, Bucharest 050095, Romania

Abstract. In this paper we analyse an important event in the life cycle of the pulsatory liposome: the membrane rupture for pore opening. An unilamellar lipid liposome filled with an aqueous solution of an impermeant solute was introduced into a hypotonic aqueous medium. Due to transbilayer osmotic imbalance, water flows inside the liposome and swells it up to a critical size, when the upper elasticity limit of the bilayer is reached. In this state the membrane suddenly ruptures and a transbilayer pore appears. A part of the intracellular material leaks out through this pore and the liposome membrane relaxes and, finally, recovers. The pore appearance in spherical bilayers is a more intricate process compared to plane lipid bilayers. Here we have studied the influence of membrane stretching on the pore appearance. We have also calculated the energetic barrier for a pore opening and closing. The stability of the liposome with a pore on it was analyzed.
Key words: Stretched vesicle, pulsatory vesicle, energetic barriers, pore opening, pore closing

Corresponding author’s e-mail: popescu1947@yahoo.com

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