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Constant Pressure-controlled Extrusion Method for the Preparation of Nano-sized Lipid Vesicles
Published on: June 22, 2012
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Several common methods of making vesicles (except an emulsion method) capture intended lipid ratios
Heidi M J Weakly1, Kent J Wilson1, Gunnar J Goetz1
1Department of Chemistry, University of Washington, Seattle, Washington.
Biophysical Journal
|August 28, 2024
Summary
Different methods for creating giant unilamellar vesicles (GUVs) can alter lipid ratios. Mass spectrometry revealed emulsion transfer significantly changes cholesterol and saturated PC-lipid levels, impacting experimental reproducibility.
Area of Science:
- Biophysics
- Materials Science
- Analytical Chemistry
Background:
- Giant unilamellar vesicles (GUVs) are crucial models for cell membranes.
- Diverse GUV formation methods exist, each with potential impacts on lipid composition.
- Consistent lipid ratios are essential for reproducible GUV experiments.
Purpose of the Study:
- To quantify lipid ratios in GUVs produced by five common methods.
- To compare these ratios against a common stock lipid mixture.
- To assess the impact of GUV formation technique on lipid composition.
Main Methods:
- Preparation of GUVs using electroformation (ITO slides, Pt wires), gentle hydration, emulsion transfer, and extrusion.
- Analysis of lipid ratios in vesicle solutions via mass spectrometry.
- Use of five-component and binary lipid mixtures including saturated/unsaturated PC-lipids, PG, PE, and cholesterol.
Main Results:
- ITO electroformation, Pt electroformation, gentle hydration, and extrusion methods showed minor lipid ratio shifts (≤5 mol%).
- Emulsion transfer significantly reduced cholesterol (~80%) and increased saturated PC-lipid abundance.
- Binary mixture experiments largely supported findings from the five-component mixture.
Conclusions:
- Lipid ratios in GUVs are highly sensitive to the formation method, especially emulsion transfer.
- Small increments in lipid ratios can lead to technique-dependent data and sample variations.
- Experiments exploring broad lipid ratio ranges or general trends are less affected by method choice.
