Probing Deuteration-Induced Phase Separation in Supported Lipid Monolayers using Hyperspectral TERS Imaging

Area of Science:

• Membrane biophysics
• Lipid self-assembly
• Nanoscale surface science

Background:

• Biological membranes' complex organization is vital for cellular functions.
• Lipid tail length and cholesterol concentration influence membrane domain formation.
• Deuterium labeling aids in studying cellular structures but its effect on lipid phase separation is unclear.

Purpose of the Study:

• To investigate the impact of lipid deuteration on phase-separated domain formation in supported lipid monolayers.
• To explore how deuterium labeling affects lipid tail behavior and phase separation.
• To demonstrate the utility of hyperspectral Tip-Enhanced Raman Spectroscopy (TERS) for analyzing lipid membranes.

Main Methods:

• Utilizing hyperspectral Tip-Enhanced Raman Spectroscopy (TERS) imaging.
• Analyzing 1:1 mixed monolayers of dipalmitoylphosphatidylcholine (DPPC) and deuterated DPPC on Au(111) surfaces.
• Employing label-free nanoanalytical techniques.

Main Results:

• Observed partial segregation of domains enriched in deuterated and nondeuterated lipids.
• Demonstrated that deuteration influences lipid phase behavior in supported monolayers.
• Confirmed TERS as a powerful tool for nanoscale lipid membrane analysis.

Conclusions:

• Lipid deuteration can induce partial segregation in lipid monolayers, impacting phase behavior.
• Subtle structural modifications like deuteration can significantly alter lipid phase separation.
• Hyperspectral TERS is a valuable, non-destructive method for advancing membrane biophysics research.