Cholesterol-induced condensing and disordering effects on a rigid catanionic bilayer: a molecular dynamics study

Area of Science:

• Biophysics
• Materials Science

Background:

• Catanionic vesicles are self-assembled structures with potential applications in drug delivery.
• Understanding their structural properties is crucial for optimizing their function.

Purpose of the Study:

• To investigate the effects of cholesterol on the bilayer properties of hexadecyltrimethylammonium-dodecylsulfate (HTMA-DS) catanionic vesicles.
• To analyze the molecular organization, orientation, and conformation within the vesicle bilayer.

Main Methods:

• Molecular dynamics simulations were employed to study the HTMA-DS/cholesterol system.
• Analysis of simulation trajectories provided insights into structural properties.

Main Results:

• Cholesterol induced both condensing and disordering effects on the HTMA-DS bilayer.
• Condensing effect: Increased contact between cholesterol and hydrocarbon chains enhanced order.
• Disordering effect: Increased head group distance, void formation, and conformational changes led to disorder, especially at high cholesterol content.

Conclusions:

• Cholesterol has a dual effect on HTMA-DS catanionic vesicle bilayers.
• At high concentrations, cholesterol's disordering effect dominates, impacting vesicle structure and dynamics.