Development of functional nanomaterials is of great importance and significance for
advanced drug delivery and therapy. Nevertheless, exogenous nanomaterials have a great
ability to induce undesired immune responses and nano-protein interactions, which
may result in toxicity and failure of therapy. Exosomes, a kind of endogenous extracellular
vesicle (40-100 nm in diameter), are considered as a new generation of a natural nanoscale
delivery system. Exosomes secreted by different types of cells carry different signal
molecules (such as RNAs and proteins) and thus have a great potential for targeted
drug delivery and therapy. Herein, we provide comprehensive understanding of the properties
and applications of exosomes, including their biogenesis, biofunctions, isolation,
purification, and drug loading, and typical examples in drug delivery and therapy.
Furthermore, their advantages compared to other nanoparticles and potential in tumor
immunotherapy are also discussed. STATEMENT OF SIGNIFICANCE: Exosomes, a kind of endogenous
extracellular vesicle, have emerged as a novel and attractive endogenous nanomaterial
for advanced drug delivery and targeted therapy. Exosomes are secreted by many types
of cells and carry some unique signals obtained from their parental cells. Furthermore,
the liposome-like structure allows exosomes to load various drugs. Hence, the potential
of exosomes in drug delivery, tumor targeted therapy, and immunotherapy has been investigated
in recent years. On the basis of their endogenous features and multifunctional properties,
exosomes are of great significance and interest for the development of future medicine
and pharmaceuticals.