Surface response methodology for the study of supported membrane formation

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Membrane Biophysics

Background:

• Tethered lipid bilayers (tBLMs) are crucial biomimetic models for studying membrane proteins and cellular processes.
• Formation of stable and defect-free tBLMs on various surfaces remains a challenge.
• Vesicle deposition offers a promising route for tBLM fabrication.

Purpose of the Study:

• To investigate the formation of tethered lipid bilayers via vesicle deposition on amine-functionalized surfaces.
• To optimize the preparation parameters for continuous and defect-free tBLMs.
• To establish a versatile and easily obtainable biomimetic membrane model.

Main Methods:

• Utilized egg-PC vesicles with specific anchoring molecules (DSPE-PEG-NHS) on amine-coated surfaces (gold and glass).
• Employed a Doehlert experimental design to study factors influencing bilayer formation: lipid concentration, anchoring molecule percentage, contact time, and resting time.
• Monitored bilayer formation using surface plasmon resonance spectroscopy and fluorescence recovery after photobleaching.

Main Results:

• Identified an optimal experimental domain for tBLM formation: 0.1-1 mg/mL lipid concentration, 4-8% anchoring molecules, 1-4 h contact time, and 21-24 h resting time.
• Characterized the resulting membranes by thickness, diffusion coefficient (2.5-3.6 x 10^-8 cm^2/s), and mobile fraction (94-99%).
• Atomic force microscopy confirmed the formation of continuous and homogeneous bilayers within the optimized parameters.

Conclusions:

• A robust and reproducible method for creating high-quality tethered lipid bilayers using vesicle deposition was established.
• The optimized parameters yield stable biomimetic membranes suitable for protein studies.
• This versatile tBLM formation strategy is adaptable to different substrates, enhancing its applicability in biosensing and research.