Pore nucleation in mechanically stretched bilayer membranes.

Area of Science:

• Computational Biophysics
• Membrane Biophysics
• Materials Science

Background:

• Understanding pore formation in lipid bilayers is crucial for membrane function and stability.
• Previous studies suggest pore dynamics involve surface and line tension, but microscopic details remain debated.

Purpose of the Study:

• To investigate the free-energy barrier for pore nucleation in bilayer membranes via computer simulations.
• To analyze the transition of pore hydrophobicity and estimate line tension at different scales.

Main Methods:

• Utilized computer simulations to model pore nucleation under constant lateral pressure.
• Calculated free-energy barriers to determine pore characteristics and estimate line tension.

Main Results:

• Identified a transition from hydrophobic to hydrophilic character in nucleating pores as they grow.
• Confirmed pore growth and closure dynamics are governed by surface and line tension.
• Estimated line tension, showing good agreement with experimental data and highlighting differences between microscopic and macroscopic values.

Conclusions:

• Bilayer pore nucleation does not appear to involve a metastable intermediate.
• Distinguishing microscopic and macroscopic line tension is essential for accurate theoretical models.
• Simulation results provide valuable insights into lipid bilayer mechanics and pore formation.