Exosomes are extracellular vesicles released by cells in the body. Exosomes act as intercellular
messengers delivering a variety of materials including RNA, Proteins, etc.
Extracellular vesicles, secreted by almost every cells, are classified into three groups depending on their size;
exosome(50 – 200nm), microvesicle (200 - 1000nm), apoptotic body(800 – 5000nm).
Exosomes are produced by unique mechanisms, compared to the other types of extracellular vesicles. They invaginate into an endosome, then secreted
from cell surface to extracellular space after completion of maturation period in endosome. This whole process endows exosomes certain characteristics
as follows; first, defined range of size. Second, incorporation of certain types of membrane proteins. Lastly, inclusion of various cell-derived molecules,
such as proteins, lipid, and RNA, in their lumen. Exosomes can modify biological functions of recipient cells upon arrival either by cellular uptake into
cytoplasm or protein-to-protein signaling at the cell surface.
Exosome-based Drug-Delivery System
Although many drug delivery systems have been tested, the limitations of therapeutic modalities have rendered many of them intractable.
Exosomes as a drug delivery vehicle have exclusive advantages over others as follows;
Exosomes can evade host immune
system, thereby increasing stability of
Exosomes can mediate intercellular
communication between cells, thereby
suitable for intracellular drug delivery.
Exosomes are derived from cells of
live animal, thereby it has high
Exosomes can pass through
blood-brain-barrier, thereby it has high
potential to be a successful treatment
of neurological disease.