Purification and Fluorescent Labeling of Exosomes

Abstract

Exosomes are small membrane vesicles of endocytic origin secreted into the extracellular environment from a variety of different cells, and are thought to play important roles in intercellular communications. Here, we provide a useful protocol to purify the exosomes released from cell lines using sucrose gradient centrifugation. In this protocol, we also applied a red-fluorescent lipophilic dye, DiI, which is incorporated in the outer membrane of exosomes. This fluorescently labeled exosomes allow us to visualize individual exosomes by a confocal laser scanning microscope.