Exosomes in Drug Delivery

A tremendous number of therapeutic molecules and vaccines have been generated in the last few decades. This level of production necessitates an effective and safe drug delivery system (DDS). Designing a DDS for the specific targeting of organs and for passing through the blood-brain barrier remains a challenge. Several drug carriers have been tested, such as silver- and gold-coated nanoparticles, liposomes and exosomes. Among these, exosomes have received much attention due to their natural composition, outstanding safety and efficient crossing of the blood-brain barrier. A considerable number of studies, including clinical trials, have described the use of exosomes as vehicles for several drug constituents, such as proteins, small molecules, ribonucleic acids (RNAs) and deoxyribonucleic acid (DNA). Despite great accomplishments in the application of exosomes, many challenges, such as induced cytotoxicity, undesired interactions and the production of sufficient quantities for clinical use require further research. In the current chapter, a number of issues regarding the use of exosomes for drug delivery are discussed. The composition, characterization and functions of exosomes are reviewed. We focus on exosomes as vehicles for delivering different drug molecules. In addition, the major advantages and disadvantages associated with the use of exosomes as therapeutic drug vehicles are addressed.