Lipid Domain Co-localization Induced by Membrane Undulations

Area of Science:

• Biophysics
• Materials Science
• Soft Matter Physics

Background:

• Multicomponent lipid bilayers exhibit complex phase transitions and lipid domain formation.
• Co-localization of lipid domains in opposing membrane leaflets suggests interleaflet coupling.
• Understanding this coupling is crucial for membrane function and stability.

Purpose of the Study:

• To investigate the role of fluctuation-induced interactions in co-localizing lipid domains across membrane leaflets.
• To quantify the magnitude and robustness of this interleaflet coupling mechanism.

Main Methods:

• Theoretical investigation employing a mode-counting argument.
• Perturbative and non-perturbative calculations for specific model systems.
• Analysis of domain interactions within lipid bilayer membranes.

Main Results:

• Fluctuation-induced interactions between leaflet domains provide a robust mechanism for co-localization.
• Spatial variations in membrane bending rigidity drive an attractive interleaflet coupling (∼0.01k_BT/nm²).
• This coupling is resilient to changes in membrane tension and substrate interactions.

Conclusions:

• Fluctuation-induced interactions are a significant factor in lipid domain organization in bilayers.
• The identified coupling mechanism offers a fundamental explanation for observed domain co-localization.
• This finding has implications for understanding membrane self-assembly and function.