Phospholipid Epitaxial Assembly Behavior on a Hydrophobic Highly Ordered Pyrolytic Graphite Surface

Area of Science:

• Materials Science
• Biophysics
• Surface Chemistry

Background:

• Supported lipid bilayers (SLBs) are crucial cell membrane models.
• Existing SLB models primarily offer top-down views, limiting side-view analysis.
• A method for side-view observation of phospholipid membranes is needed.

Purpose of the Study:

• To develop a novel method for constructing side-view phospholipid membranes.
• To investigate the self-assembly of phospholipids on highly ordered pyrolytic graphite (HOPG).
• To enable direct observation of membrane structure and modification of 2D materials.

Main Methods:

• Spin coating technique to create phospholipid striped lamella on HOPG.
• Atomic force microscopy (AFM) for structural analysis.
• Molecular dynamics (MD) simulations for self-assembly studies.

Main Results:

• Phospholipids with varying properties epitaxially adsorb onto HOPG.
• A 0.1 mg/mL concentration of Plasm PC forms a 5.93 ± 0.21 nm wide monolayer.
• Increased concentration to 1 mg/mL results in stable four-striped layers.
• DOPS multilayers exhibit greater width than electroneutral lipids due to electrostatic repulsion.

Conclusions:

• A universal strategy for side-view membrane observation was established.
• This method facilitates the modification of 2D materials with amphiphilic biomolecules.
• The findings offer new insights into phospholipid self-assembly and membrane structure.