Book of Abstracts: Albany 2009
June 16-20 2009
© Adenine Press (2008)
Stability of Bilayer Lipid Membrane Under a Combined Effect of Electric Field and Hydrostatic Pressure
The issue of stability of cell membranes is central in membranology. The extreme complexity of cell membranes makes is reasonable to study this problem through a model - a bilayer lipid membrane (BLM). The overwhelming majority of works focuses on studying BLM stability in electric field. However, it is well known that often the membrane is impacted by both electric force and hydrostatic pressure. Experimental and theoretical studies have been carried out to investigate the combined effect of hydrostatic pressure and trans-membrane difference of potentials on BLM stability. As a parameter characterizing the BLM stability level, assumed is average lifetime of BLM at given values of electrostatic field and hydrostatic pressure. As demonstrated experimentally, the combined action of electrostatic field and hydrostatic pressure results in a drastic decrease of average lifetime of BLM. A theoretical description of the BLM stability loss has been given analogously to the theory of thin membrane stability based on the concepts on formation and extra-critical growth of through hydrophile pores. Pores in BLM form spontaneously, and then - as result of randomized changes in their dimensions - reach some critical size, after which BLM looses its stability. We have calculated the energetic barrier of hydrophile pore formation in the presence of both trans-membrane difference of potentials and hydrostatic pressure on BLM. As demonstrated, the height of the barrier and critical radius of the pore drastically decreases depending on the growth of both trans-membrane difference of potentials and the value of hydrostatic pressure. The analytical expression has been derived for average lifetime of BLM under a combined impact of electrostatic field and hydrostatic pressure. It is demonstrated, too, that average lifetime of BLM exponentially reduces depending on the growth of trans-membrane difference of potentials and hydrostatic pressure.
1Yerevan State University