Molecular dynamics simulation of interlayer water embedded in phospholipid bilayer

Area of Science:

• Biophysics
• Materials Science
• Computational Chemistry

Background:

• Lipid bilayers are fundamental to cell membranes.
• Understanding membrane permeability is crucial for drug delivery and biological processes.
• Water's role in membrane dynamics, particularly pore formation, remains an active research area.

Purpose of the Study:

• To investigate the mechanism of pore structure formation in a 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayer.
• To determine the critical factors influencing water molecule escape from the hydrophobic region of a lipid bilayer.
• To establish the relationship between lipid membrane rigidity and pore formation.

Main Methods:

• Molecular dynamics simulation of a 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayer at 300K.
• Observation of water molecule behavior and lipid bilayer deformation during simulated water escape.
• Analysis of the critical water layer thickness for pore formation and membrane rupture.

Main Results:

• Water molecules transformed from a slab to a cylindrical droplet within the hydrophobic region.
• This transformation locally deformed the lipid monolayer, preceding pore formation.
• Increased interlayer water thickness beyond a critical value suppressed deformation, leading to bilayer rupture.
• Pore formation was directly linked to the lipid membrane's local deformation and rigidity.

Conclusions:

• Lipid membrane pore formation is intrinsically linked to local deformations driven by water molecule dynamics.
• The rigidity of the lipid membrane plays a critical role in regulating local permeability and preventing bilayer rupture.
• This study provides insights into the mechanical properties of lipid membranes and their influence on permeability.