Large vesicle contamination in small, unilamellar vesicles

Area of Science:

• Lipid bilayer research
• Nanoparticle characterization
• Biophysical chemistry

Background:

• Small, unilamellar vesicles (SUVs) are crucial in drug delivery and biomimetic studies.
• Accurate characterization of SUV size and purity is essential for reliable applications.
• Existing methods for detecting large, multilamellar vesicle (LMVs) contamination can be complex or require specialized equipment.

Purpose of the Study:

• To develop a novel, accessible method for quantifying LMV contamination in SUV preparations.
• To characterize SUVs prepared using a new sonication technique that avoids probe contamination.
• To establish a reliable assay using standard spectrophotometry.

Main Methods:

• Preparation of SUVs using a high-power cup sonifier without titanium probe contact.
• Characterization of vesicle size and purity via gel filtration chromatography and high-speed centrifugation.
• Turbidity measurements at varying wavelengths (300-650 nm) to analyze vesicle scattering properties.

Main Results:

• Vesicle turbidity plots exhibited linear relationships with wavelength, indicating SUV purity.
• The presence of LMVs introduced measurable intercepts, quantitatively proportional to LMV concentration.
• The assay demonstrated high sensitivity for detecting minute quantities of contaminating LMVs.

Conclusions:

• A simple, cost-effective spectrophotometric assay effectively quantifies LMV contamination in SUV preparations.
• The new sonication method yields SUVs free from probe-derived contaminants.
• This assay facilitates improved quality control for SUV production and research.