Nanostar self-assemblies of spherical nanoparticles inside lipid vesicles

Area of Science:

• Biophysics
• Materials Science
• Computational Chemistry

Background:

• Nanoparticle (NP) adhesion to lipid membranes induces curvature deformations, leading to NP-NP interactions and self-assembly.
• Previous studies indicate attractive interactions for NPs on the outer leaflet of lipid vesicles, forming linear chains.

Purpose of the Study:

• To investigate the interaction and self-assembly behavior of NPs adhering to the inner leaflet of lipid vesicles.
• To explore the phase diagram of NP configurations based on NP number and adhesion strength.

Main Methods:

• Coarse-grained molecular dynamics simulations were employed.
• Systematic simulations were performed varying the number of NPs and their adhesion strength to the membrane.

Main Results:

• Spherical NPs on the inner leaflet of lipid vesicles exhibit repulsive interactions, leading to configurations where NPs are spatially separated.
• A phase diagram revealed distinct adhesion modes: 3D clustering (dynamic to rigid) and a novel 2D clustering mode.
• The 2D clustering mode results in ordered planar nanostars, with NP geometry dictated by NP count and anisotropic wrapping.

Conclusions:

• The interaction dynamics of NPs differ significantly between the inner and outer leaflets of lipid vesicles.
• The study identifies novel 2D nanostar self-assembly driven by NP repulsion on the inner vesicle leaflet.
• Adhesion strength and NP number are critical factors controlling NP self-assembly into diverse configurations.