Background: Exosomes open exciting new opportunities for advanced drug transport and targeted
release. Furthermore, exosomes may be used for vaccination, immunosuppression or wound healing. To fully
utilize their potential as drug carriers or immune-modulatory agents, the optimal purity of exosome preparations
is of crucial importance.
Methods: Articles describing the isolation and purification of exosomes were retrieved from the PubMed database.
Results: Exosomes are often separated from biological fluids containing high concentrations of proteins, lipids
and other molecules that keep vesicle purification challenging. A great number of purification protocols have
been published, however, their outcome is difficult to compare because the assessment of purity has not been
standardized. In this review, we first give an overview of the generation and composition of exosomes, as well as
their multifaceted biological functions that stimulated various medical applications. Finally, we describe various
methods that have been used to purify small vesicles and to assess the purity of exosome preparations and critically
compare the quality of these evaluation protocols.
Conclusion: Combinations of various techniques have to be applied to reach the required purity and quality control
of exosome preparations.