Shockwave-induced structural changes of lipid flat disk and transition to vesicle

Area of Science:

• Biophysics
• Materials Science
• Computational Chemistry

Background:

• Lipid vesicles are vital in drug delivery and nanotechnology.
• Sonication is a common method for producing nanosized vesicles.
• Understanding the physical mechanisms of vesicle formation is key to controlling size and properties.

Purpose of the Study:

• To investigate the structural transformations of lipid flat disks under shock wave impact.
• To elucidate the role of shock wave parameters (intensity, angle) in these transformations.
• To establish a link between shock-induced lipid disk changes and subsequent vesicle formation.

Main Methods:

• Non-equilibrium molecular dynamics (NEMD) simulations were employed.
• Coarse-grained saturated phospholipid models formed the lipid disk (approx. 30 nm diameter, gel phase).
• Piston-driven method simulated shock waves (piston speed ≤ 1.0 km/s).

Main Results:

• Shock wave interaction with lipid disks is dependent on impact angle and shock intensity.
• Parallel impact (rotation axis // shock) thins the disk; perpendicular impact causes radial compression and ellipticity.
• Shock waves induce lipid disordering, suggesting a gel-to-liquid phase transition.
• Vesicle formation is influenced by shock intensity and induced disk anisotropy.

Conclusions:

• Shock waves can induce significant structural changes and phase transitions in lipid disks.
• Impact angle and shock intensity are critical factors in controlling these changes.
• The findings provide insights into controlling vesicle size and formation during sonication.