Supported phospholipid/alkanethiol biomimetic membranes: insulating properties

Area of Science:

• Biophysics
• Materials Science
• Surface Chemistry

Background:

• Model lipid bilayer membranes are crucial for understanding cell membrane properties.
• Existing methods for creating these membranes often involve organic solvents and can be unstable.
• A need exists for a stable, easily prepared model membrane system.

Purpose of the Study:

• To develop a novel, stable, and solvent-free supported hybrid bilayer membrane.
• To characterize the insulating properties of this new model membrane.
• To assess the impact of membrane perturbants on the bilayer's insulating capabilities.

Main Methods:

• Formation of supported hybrid bilayers by adding phospholipid vesicles to alkanethiol monolayers on gold.
• Characterization using electron transfer rate measurements and impedance spectroscopy.
• Analysis of capacitance to determine dielectric constant.

Main Results:

• The supported hybrid bilayer membrane is rugged, stable, and reproducibly prepared without organic solvents.
• The membrane exhibits pinhole-free structure with conductivity and resistivity values comparable to black lipid membranes.
• Capacitance measurements indicate a dielectric constant of 2.7.
• The protein toxin melittin disrupted the insulating properties without altering bilayer structure.

Conclusions:

• A novel, stable, and solvent-free supported hybrid lipid bilayer membrane has been successfully developed.
• This model membrane accurately reflects the insulating properties of natural lipid membranes.
• The system provides a valuable platform for studying the effects of various perturbants on lipid membrane function.