Poster Presentation 2014 International Biophysics Congress

Effects of electrostatic interactions on tension-induced pore formation in single GUVs (#608)

Taka-aki Tsuboi 1 , Mohammad Abu Sayem Karal 2 , Victor Levadny 2 3 , Marina Belaya 3 , Masahito Yamazaki 1 2 4
  1. Department of Physics, Graduate School of Science, Shizuoka University, Shizuoka, Japan
  2. Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan
  3. Theoretical Problem Center of Physico-Chemical Pharmacology, Russian Academy of Sciences, Kosugina, Moscow, Russia
  4. Research Institute of Electronics, Shizuoka University, Shizuoka, Japan

The rate constant (kp) of tension-induced pore formation in lipid membranes is one of the important measures to consider the mechanical stability of lipid membranes or biomembranes. Recently, we analyzed the time-course of the fraction of intact giant unilamellar vesicles (GUVs) among all the GUVs under constant tension σ induced by micropipette aspiration, and obtained values of kp as a function of σ1 . We also developed a theory to determine kp using the mean first passage time. The fitting of the theoretical curves of kp vs. σ to the experimental data determined the line tension of a pre-pore1 . Here, we investigated the effects of the electrostatic interactions on the rate constant of tension-induced pore formation in lipid membranes. The decrease in salt concentration increased the kp values of 40% dioleoylphosphatidylglycerol(DOPG)/60%dioleoylphosphatidylcholine(DOPC)-GUVs (e.g., at σ = 5 mN/m, 1.9×10-2, 1.7×10-3, and 0 s-1 in 0, 150, and 300 mM NaCl, respectively) in a physiological buffer. The increase in surface charge density of DOPG/DOPC-GUVs increased kp values in 150 mM NaCl in buffer. These data indicate that kp increases as the electrostatic interactions due to the surface charges increase. We discuss the mechanism of the effects of the electrostatic interactions on kp.

  1. Langmuir, 29, 3848, 2013