Targeting of therapeutic agents to their specific site of action not only increases the treatment
efficacy, but also reduces systemic toxicity. Therefore, various drug delivery systems (DDSs)
have been developed to achieve this target. However, most of those DDSs have several issues regarding
biocompatibility and environmental hazard. In contrast to the synthetic DDSs, exosome-based
natural carriers are biocompatible, biodegradable and safe for the environment. Since exosomes play a
role in intercellular communication, they have been widely utilized as carriers for different therapeutic
agents. This article was aimed to provide an overview of exosomes as an environment-friendly DDS
in terms of engineering, isolation, characterization, application and limitation.