Phospholipid vesicle fusion on micropatterned polymeric bilayer substrates

Area of Science:

• Biomembrane modeling
• Materials science
• Surface chemistry

Background:

• Development of versatile model systems for biological membranes is crucial for understanding cellular processes.
• Substrate-supported planar lipid bilayers (SPBs) offer a platform for membrane studies, but creating stable, versatile systems remains a challenge.
• Photolithographic polymerization of diacetylene phospholipids provides a novel approach to create patterned lipid bilayers.

Purpose of the Study:

• To investigate the incorporation of fluid lipid bilayers into micropatterned polymeric bilayer matrices.
• To understand the mechanism of vesicle fusion and its acceleration on patterned substrates.
• To confirm the formation of continuous hybrid bilayer membranes.

Main Methods:

• Micropatterning of substrate-supported planar lipid bilayers (SPBs) using photolithographic polymerization of a diacetylene phospholipid.
• Observation of vesicle fusion using total internal reflection fluorescence microscopy.
• Monitoring vesicle-to-SPB transformation using quartz crystal microbalance with dissipation monitoring (QCM-D).

Main Results:

• Vesicle fusion initiated at the boundaries of polymeric bilayers and spread into lipid-free regions.
• The presence of micropatterned polymeric bilayers significantly accelerated the transformation of adsorbed vesicles into SPBs.
• Polymeric bilayer edges were shown to catalyze SPB formation by destabilizing vesicles.

Conclusions:

• The study demonstrates a novel method for creating hybrid bilayer membranes with embedded fluid lipid bilayers.
• Polymeric bilayer edges play a catalytic role in accelerating the formation of fluid bilayers from vesicles.
• The results support the formation of continuous, stable hybrid membranes, sealing energetically unfavorable edges.