Exosome Standard: Fluorescent Exosomes EGFP-CD63

Introduction
Exosomes are small extracellular vesicles that are released from cells upon fusion of an intermediate endocytic compartment, the multivesicular body (MVB) 1 , with the plasma membrane. They are thought to provide a means of intercellular communication (2,3) and of transmission of macromolecules between cells allowing the spread of proteins, lipids, mRNA, miRNA and DNA and as contributing factors in the development of several diseases. Exosomes can also modulate cancer microenvironment (4) and the immune response (5,6) .Fluorescent exosomes are labelled by expressing a specific exosome membrane marker (such as CD63) fused to a fluorescent protein (i.e. EGFP) in 293F cells.

Lyophilized Fluorescent Exosomes:
Freeze-dried fluorescent exosomes are extracellular vesicles (EVs) with an average particle size of 150 nm that express tetraspanins fused to a fluorescent protein (FP) marker: EGFP-CD63 (green) or mScarlet-CD81 (red). They are obtained by ultracentrifugation from transfected 293F cells expressing the FP-tetraspanin fusion protein in their membrane. The fluorescent exosomes are highly stable and can be used as reference material for EV analysis or for in vitro screening studies.