Lipid exchange enhances geometric pinning in multicomponent membranes on patterned substrates

Area of Science:

• Soft Matter Physics
• Materials Science
• Biophysics

Background:

• Supported lipid bilayers (SLBs) exhibit domain organization influenced by substrate curvature.
• Theoretical models link domain behavior in closed SLBs to topology.
• Understanding these relationships is crucial for biomimetic materials and nanotechnology.

Purpose of the Study:

• To investigate the role of geometry and thermodynamic openness on lipid domain organization in SLBs.
• To test the hypothesis that closed topology is essential for curvature-induced domain effects.
• To quantify the influence of colloid geometry on the free-energy landscape and domain pinning.

Main Methods:

• Fabrication of SLBs on colloidal particles of varying shapes on a flat substrate.
• Creation of thermodynamically open systems allowing local lipid exchange.
• Reconstruction of Gibbs phase diagrams and combination with numerical data.

Main Results:

• Colloid geometry directly influences the free-energy landscape of the lipid bilayer.
• Local lipid exchange enhances pinning of liquid disordered domains in curved regions.
• Estimates for the bending moduli difference between lipid domains were obtained.

Conclusions:

• The hypothesis regarding closed topology's necessity for curvature effects is challenged.
• Thermodynamically open systems provide new insights into lipid bilayer behavior.
• Catenoidal and conical geometries show potential for improving bending moduli measurements.