Phase Separation and Nanodomain Formation in Hybrid Polymer/Lipid Vesicles

Area of Science:

• Materials Science
• Biophysics
• Polymer Chemistry

Background:

• Hybrid polymer/lipid vesicles combine properties of both components.
• Understanding nanoscale organization is crucial for vesicle function.
• Previous studies showed instability in giant hybrid vesicles.

Purpose of the Study:

• To investigate nanoscale phase separation in hybrid polymer/lipid large unilamellar vesicles (LUVs).
• To identify factors contributing to the stability of nanodomains within these hybrid structures.
• To explore the influence of membrane properties and curvature on hybrid vesicle behavior.

Main Methods:

• Small Angle Neutron Scattering (SANS) for structural analysis.
• Time-Resolved Förster Resonance Energy Transfer (TR-FRET) for dynamics and proximity.
• Cryo-Transmission Electron Microscopy (cryo-TEM) for high-resolution imaging.

Main Results:

• Direct evidence of nanoscale phase separation in hybrid LUVs was observed.
• Formation of stable nanodomains enriched in either lipid or polymer components.
• Minimized hydrophobic mismatch due to matching membrane thicknesses contributed to domain stability.

Conclusions:

• Nanoscale phase separation and stable nanodomain formation are achievable in hybrid polymer/lipid LUVs.
• Matching membrane thicknesses are critical for stabilizing these nanodomains.
• Vesicle curvature likely plays a role in the observed differences between LUVs and GUVs, influencing nanodomain stability.