Interfacial behavior of phospholipid monolayers revealed by mesoscopic simulation

Area of Science:

• Computational Chemistry
• Materials Science
• Biophysics

Background:

• Phospholipid monolayers at the air-water interface are crucial for biological membranes.
• Accurate simulation of these systems is computationally demanding.
• Existing coarse-grained models lack quantitative accuracy.

Purpose of the Study:

• To develop a mesoscopic model for simulating dipalmitoyl phosphatidylcholine (DPPC) and palmitoyl oleoyl phosphatidylcholine (POPC) monolayers.
• To validate the model's accuracy against experimental data and all-atom simulations.
• To provide a computationally efficient method for studying complex phospholipid systems.

Main Methods:

• Many-body dissipative particle dynamics (MDPD) simulations were employed.
• Model parameterization was based on reproducing physical properties of water, alkanes, and interfacial phospholipid behavior.
• Simulations focused on surface pressure-area isotherms, morphologies, compressibility modulus, order parameters, and monolayer thickness.

Main Results:

• MDPD simulations achieved accuracy comparable to all-atom simulations and experiments with significantly reduced computational cost.
• The model accurately reproduced surface pressure-area isotherms and pressure-related morphologies.
• Quantitative agreement was found for compressibility modulus, lipid tail order parameters, and monolayer thickness.
• The model successfully captured the behavior of mixed DPPC/POPC monolayers with varying compositions.

Conclusions:

• The developed MDPD mesoscopic model provides a quantitatively accurate and computationally efficient approach for simulating phospholipid monolayers.
• This model shows significant promise for studying complex natural phospholipid systems and advancing our understanding of lipid behavior at interfaces.