A Study of Liposome Structure Changes with Temperature Using Non-Equilibrium Molecular Dynamics Simulations.

Area of Science:

• Biophysics
• Materials Science
• Nanotechnology

Background:

• Liposomes are versatile nanocarriers for drug delivery systems (DDS).
• Controlled drug release from liposomal DDS often relies on temperature-induced structural changes.
• Existing experimental and simulation methods face limitations in accurately assessing temperature effects on whole liposome structures.

Purpose of the Study:

• To investigate the impact of localized temperature increases within different liposome regions on structural integrity.
• To elucidate the molecular-level mechanisms governing temperature-induced liposome destabilization.
• To evaluate the influence of lipid tail unsaturation on liposome responses to thermal stimuli.

Main Methods:

• Established and simulated whole spherical liposome models using molecular dynamics (MD).
• Simulated temperature variations localized to the inner water core, lipid bilayer, and exterior.
• Analyzed changes in lipid dynamics, positional distribution, density, and inter-molecular interactions.

Main Results:

• Temperature increase in the lipid bilayer induced the largest changes in liposome structure.
• This included increased lipid strand sway, altered lipid positions, decreased lipid/water density, and reduced lipid-lipid/lipid-water interactions.
• Higher lipid tail unsaturation led to greater structural changes due to reduced lipid packing and interactions.

Conclusions:

• Localized heating of the lipid bilayer is most effective for destabilizing liposomes.
• Lipid unsaturation significantly influences temperature-dependent liposome structural dynamics.
• Findings provide crucial insights for optimizing liposomal DDS design for enhanced drug delivery.