Size distribution of extracellular vesicles by optical correlation techniques

Area of Science:

• Biotechnology
• Nanotechnology
• Biophysics

Background:

• Extracellular vesicles (EVs) are vital for biological processes, with their colloidal properties influencing fundamental research and clinical applications.
• Accurate characterization of EV size distribution and colloidal stability is challenging due to their wide size range, varying concentrations, membrane properties, and potential contaminants like protein aggregates.

Purpose of the Study:

• To develop and present a detailed, accurate, and robust protocol for determining the size distribution and colloidal stability of extracellular vesicles (EVs).
• To address the limitations in current methods for EV characterization, particularly concerning contaminants and the broad range of EV sizes.

Main Methods:

• The study employs a combination of Fluorescence Correlation Spectroscopy (FCS) and Dynamic Light Scattering (DLS) for comprehensive EV analysis.
• A detailed protocol covering theoretical background, critical experimental steps, and data analysis procedures is provided.

Main Results:

• The presented protocol enables accurate and robust determination of EV size distribution and stability.
• The method was successfully illustrated using EV formulations derived from B16 melanoma cells, a model for skin cancers.

Conclusions:

• The combined FCS and DLS approach offers a reliable solution for characterizing extracellular vesicle (EV) size and stability.
• This protocol advances the field of EV research, supporting the development of EV-based diagnostics and therapeutics.