Structural motifs of cholesterol nanoparticles.

Area of Science:

• Computational chemistry
• Materials science
• Biophysics

Background:

• Cholesterol is a vital lipid with complex aggregation behaviors.
• Understanding cholesterol cluster formation is key to various biological processes and material applications.

Purpose of the Study:

• To investigate the growth sequence and structural motifs of gas-phase cholesterol clusters (Ch(N)) up to N=36 molecules.
• To explore the role of intermolecular forces and solvation on cholesterol aggregate structure.

Main Methods:

• Atomistic simulations using an empirical force field model.
• Long annealing simulations from high temperatures.
• Molecular dynamics simulations for solvated clusters (water and supercritical CO2).

Main Results:

• Geometric motifs of cholesterol crystals appear in nanometric aggregates.
• Cholesterol molecules align along a common direction in clusters.
• Bilayer structures form in larger clusters due to cooperative hydrogen bonding and dispersion interactions.
• Condensation of hydrogen bonds into networks is crucial for self-organization.

Conclusions:

• Nanometric cholesterol aggregates exhibit structural characteristics of bulk crystals.
• Intermolecular forces, including hydrogen bonding and dispersion interactions, govern cluster self-organization.
• Solvation effects on medium-sized aggregates were explored in water and supercritical CO2.