Interaction of phloretin with lipid monolayers: relationship between structural changes and dipole potential change

Area of Science:

• Membrane biophysics
• Lipid-protein interactions

Background:

• Phloretin adsorbs to lipid surfaces, altering dipole potentials and membrane permeability.
• Phloretin serves as a model to study dipole potential effects on membrane permeability.

Purpose of the Study:

• Investigate phloretin interaction with lipid monolayers in different states.
• Correlate phloretin integration with dipole potential changes.
• Develop a model to explain phloretin's effect on lipid packing and surface potential.

Main Methods:

• Studied phloretin interaction with lipid monolayers (liquid-expanded and condensed states).
• Measured surface pressure and surface potential changes upon phloretin adsorption.
• Compared experimental data with static and dynamic models.

Main Results:

• Phloretin integrates into monolayers based on its aqueous concentration.
• Phloretin adsorption alters surface potential and lipid dipole moment, influenced by lipid packing.
• Surface potential changes occur independently of lipid packing alterations at higher surface pressures.
• A dynamic model significantly improves the description of experimental data compared to a static model.

Conclusions:

• Phloretin adsorption can occur without altering lipid packing.
• Lipid packing influences the phloretin-induced change in lipid dipole moment vector.
• A dynamic model is necessary to accurately describe the relationship between surface potential and lipid packing.