Viscoelastic changes measured in partially suspended single bilayer membranes

Area of Science:

• Biophysics
• Materials Science
• Biochemistry

Background:

• Biomimetic phospholipid membranes are essential for studying membrane-protein interactions.
• Key biomimetic properties include lipid mobility and inter-membrane space for protein insertion.
• Existing supported membrane models often lack these crucial biomimetic features.

Purpose of the Study:

• To develop a novel supported membrane system that mimics free bilayer membranes.
• To ensure sufficient lipid mobility and space for transmembrane protein insertion.
• To validate the biomimetic properties of the developed membrane system.

Main Methods:

• Fabrication of partially suspended DMPC (dimyristoylphosphatidylcholine) single bilayer membranes on functionalized gold surfaces.
• Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) to assess viscoelastic properties and phase transitions.
• Atomic Force Microscopy (AFM) for membrane morphology, coverage, and suspension confirmation.

Main Results:

• Successfully formed tether-free, partially suspended single bilayer membranes on gold surfaces.
• Demonstrated unrestrained lipid mobility and viscoelastic properties comparable to free bilayers via QCM-D phase transition analysis.
• AFM confirmed complete, smooth membrane coverage and the suspended nature of the membranes.

Conclusions:

• The developed partially suspended membrane system accurately represents free bilayer viscoelastic properties.
• This system provides adequate space for transmembrane protein insertion, enhancing biomimicry.
• QCM-D sensogram analysis is a reliable indicator of membrane morphology and biomimetic quality.