High coverage fluid-phase floating lipid bilayers supported by ω-thiolipid self-assembled monolayers

Area of Science:

• Biophysics
• Materials Science
• Surface Chemistry

Background:

• Large area lipid bilayers on solid surfaces are crucial for studying biological membranes.
• Minimizing substrate interactions is key, achieved by floating supported bilayers (FSBs) with an intervening water layer.
• Previous FSBs suffered from limited stability and low density.

Purpose of the Study:

• To develop a stable and dense floating supported bilayer (FSB) system on gold surfaces.
• To create a robust platform for studying membrane properties and embedded proteins.
• To overcome limitations of previous FSB formulations.

Main Methods:

• Formation of a complete self-assembled monolayer (SAM) on gold using thiol-functionalized phosphatidylcholine.
• Sequential Langmuir-Blodgett and Langmuir-Schaefer procedures for FSB formation.
• Surface plasmon resonance and neutron reflectivity (with isotopic/magnetic contrast) for characterization.

Main Results:

• A complete SAM was formed on gold surfaces.
• A highly dense FSB (>96%) of saturated phosphatidylcholine was achieved.
• FSBs from unsaturated phosphatidylcholines reached 73% coverage, a significant improvement.

Conclusions:

• The developed SAM-FSB system provides enhanced stability and density for model membranes.
• This platform enables advanced studies of transmembrane proteins and membrane potential effects.
• The method demonstrates successful formation of stable FSBs using previously challenging unsaturated lipids.