Defects in ordered aggregates of cardiolipin visualized by atomic force microscopy.

Area of Science:

• Lipid self-organization and membrane biophysics.
• Nanoscale material science and surface chemistry.

Background:

• Cardiolipin (tetra acyl diphosphatidylglycerol) is crucial for membrane structure and function.
• Understanding defects in ordered lipid aggregates informs membrane behavior and stability.

Purpose of the Study:

• To investigate defect formation and nature in cardiolipin aggregates on solid substrates.
• To analyze the influence of preparation conditions and chemical agents on lipid order.
• To explore the role of lipid oxidation in nanocrystalline order.

Main Methods:

• Utilized Atomic Force Microscopy (AFM) for nanoscale imaging of lipid aggregates.
• Studied two model systems: 3D liquid crystals and 2D self-assembled films.
• Induced defects by varying temperature and using chemicals like 2,4-dinitro-phenol (DNP) and pentachloro-phenol (PCP).

Main Results:

• AFM images characterized defect types and local densities at the nanoscale.
• Preparation temperature and chemical treatments (DNP, PCP) modulated defect formation.
• Lipid oxidation was found to affect nanocrystalline order.

Conclusions:

• AFM provides nanoscale insights into defects in cardiolipin aggregates.
• Defect formation is controllable via preparation and chemical environment.
• Elucidated the distinct roles of acyl chains and polar heads in lipid self-organization.