Generation, Characterization, and Count of Fluorescent Extracellular Vesicles.

Extracellular vesicles (EVs) are membranous particles released by all cells in the external milieu. Depending on their origin, they are given different names: exosomes are nanovesicles that originate from the endosomal compartment, whereas microvesicles bud from plasma membrane. Both contain molecules that are crucial for the onset and spreading of different pathologies, from neurodegenerative diseases to cancer, and are considered promising disease markers. On the other hand, EVs are often used as therapeutic tools, and can be engineered to carry drugs and chemicals. This chapter describes a method to produce EVs, mainly exosomes, containing the green fluorescent protein (GFP) linked to an exosome anchoring protein (Nef). This enables counting and tracing of fluorescent EVs by different methods, including conventional flow cytometry.