Vesicle size distributions measured by flow field-flow fractionation coupled with multiangle light scattering

Area of Science:

• Biophysical Chemistry
• Nanotechnology
• Materials Science

Background:

• Accurate characterization of vesicle size distribution is crucial for understanding their properties and applications.
• Existing methods for vesicle analysis often require calibration, refractive index detectors, or make assumptions about size distribution shape.

Purpose of the Study:

• To develop and validate an on-line vesicle characterization method using flow field-flow fractionation coupled with multiangle laser light scattering (flow FFF/MALLS).
• To enable simultaneous measurement of vesicle size and concentration without prior assumptions or calibration standards.
• To analyze the size distributions of vesicles produced by different formation methods.

Main Methods:

• Coupling of flow field-flow fractionation (flow FFF) with multiangle laser light scattering (MALLS) for continuous on-line analysis.
• Measurement of vesicle size and concentration as a function of elution time.
• Construction of number- and mass-weighted vesicle size distributions.

Main Results:

• The flow FFF/MALLS technique successfully determined vesicle size distributions without needing a refractive index detector or size standards.
• Vesicle size distributions were found to be non-Gaussian, fitting well to the Weibull distribution.
• Both extrusion and detergent dialysis methods produced nearly monodisperse vesicle populations (approx. 8% standard deviation) and flow FFF/MALLS resolved subpopulations with less than a twofold size difference.

Conclusions:

• Flow FFF/MALLS is a powerful, noninvasive technique for comprehensive vesicle characterization.
• The method provides accurate and detailed size distribution data, overcoming limitations of other techniques like dynamic light scattering.
• This approach facilitates a deeper understanding of vesicle formation processes and properties.