Characterization and Fine Structure of Exosomes

An exosome (30–150 nm in size) is a cell-derived nanovesicle. Extracellular vesicles are released from cells under both physiological and pathophysiological conditions. Exosomes hold molecular information which can represent their parent cell’s biological and genetic characteristics. Just as hormones and cytokines, exosomes play a key role in cellular communication or with environment to maintaining homeostasis, through the transfer of their cargo. Exosomes serve as carriers of proteins, lipids, messenger RNA (mRNA), microRNA (miRNA), and DNA to facilitate intercellular communication. Here, we describe the various methods of characterization as well as their advantages and limitations that define exosomes and we discuss their fine structure, composition, and formation, and finally, we summarize their biological functions.