Self-Assembly of Lipid Molecules under Shear Flows: A Dissipative Particle Dynamics Simulation Study

Area of Science:

• Soft Matter Physics
• Computational Chemistry
• Biomolecular Engineering

Background:

• Lipid self-assembly in aqueous solutions is fundamental to biological systems and nanotechnology.
• Understanding how external forces like shear flow affect these processes is crucial for controlling structure formation.
• Previous studies often focused on equilibrium conditions, leaving dynamic responses less explored.

Purpose of the Study:

• To investigate the self-assembly of lipid molecules in aqueous solutions under varying shear flow conditions.
• To identify the types of self-assembled structures formed under different shear regimes.
• To elucidate the influence of lipid chain length, shear flow intensity, and concentration on self-assembly pathways.

Main Methods:

• Dissipative particle dynamics (DPD) simulations were employed to model lipid molecule behavior.
• Simulations were conducted under three conditions: zero, weak, and strong shear flow.
• Phase diagrams were constructed based on lipid chain lengths to analyze equilibrium self-assembly.

Main Results:

• Various self-assembled structures were observed, including double layers, perforated double layers, hierarchical discs, micelles, and vesicles.
• Lipid chain length, shear flow strength, and solution concentration were found to significantly impact self-assembly outcomes.
• Analysis of system energy, particle number, and shape factor revealed distinct self-assembly pathways for different structures.

Conclusions:

• Shear flow is a critical factor in directing lipid self-assembly pathways and resulting morphologies.
• The findings provide insights into the dynamic behavior of lipid self-assembly relevant to biological membranes and drug delivery systems.
• This research offers potential for designing and controlling self-assembled lipid structures for biomedical applications.