Towards traceable size determination of extracellular vesicles

Area of Science:

• Biotechnology
• Nanotechnology
• Biophysics

Background:

• Extracellular vesicles (EVs) are crucial in biological processes.
• Accurate detection and characterization of EVs are hindered by their small size, low refractive index, and heterogeneity.

Purpose of the Study:

• To determine the size distribution of erythrocyte-derived EVs.
• To evaluate the performance of various techniques, including novel methods, for EV characterization.

Main Methods:

• Nanoparticle tracking analysis
• Resistive pulse sensing
• Electron microscopy
• Small-angle X-ray scattering (SAXS)
• Size exclusion chromatography coupled with dynamic light scattering

Main Results:

• Multiple techniques showed small deviations in mode values around 130 nm for erythrocyte EVs.
• Differences were observed in the reported widths of the size distributions among the methods.

Conclusions:

• Small-angle X-ray scattering (SAXS) offers potential for traceable size measurements of EVs.
• Achieving traceable EV measurements necessitates the use of monodisperse and highly concentrated samples.