Pore formation in a lipid bilayer under a tension ramp:
modeling the distribution of rupture tensions
Pierre-Alexandre Boucher 1, Bela Joos 1*, Martin J. Zuckermann 2 and Luc Fournier 3
1 University of Ottawa
2 Simon Fraser University
3 Cegep de l'Outaouais
* To whom correspondence should be addressed. E-mail: bjoos{at}science.uottawa.ca.
Submitted on June 29, 2006
Revised on August 7, 2006
Accepted on 23 January 2007
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Abstract |
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The rupture of fluid membrane vesicles with a steady ramp of micropipette suction has been shown to produce a distribution of breakage tensions, with a mean which rises rapidly with tension rate (E. Evans et al. 2003. Biophys. J.). Starting from a lattice model which incorporates the essential features of the lipid bilayers held together with hydrophobic forces, and developing it to handle varying tension rates, we reproduce the main features of the experimental results. In essence we show that the rupture kinetics are driven by the nucleation and growth of pores, with two limiting kinetics, growth limited and nucleation limited. The model has been extended to address the role of peptides in solution that can adsorb and insert themselves into the bilayer. At concentrations below those required to spontaneously rupture the membrane, the effect of the peptides is to lower the rupture tensions systematically for all tension rates.
Key Words:
lipid bilayer, modeling, peptide, pore, rupture, tension
