Emerging prospects of extracellular vesicles for brain disease theranostics

In the past decade, bio-nanoparticles inspired by nature with advantageous properties have attracted extensive interest for accurate diagnosis and effective treatment. Extracellular vesicles (EVs) are nanosized naturally derived vesicles which contain a variety of bioactive molecules reflecting their cell of origin. Emerging advances in the field of EV nanotechnology bring along novel promises for blooming the development of EV-based therapeutics. Studies of the EV features in central nervous system physiology and brain disease pathology explosively promote the idea of harnessing these endogenous vesicles as a promising strategy for brain disease theranostics. These nanosized vesicles with natural blood-brain barrier-crossability, remarkable physicochemical properties and excellent biocompatibility are considered a prime candidate as an intelligent vehicle for brain therapeutic and drug delivery applications. Here, this review provides an overview on the characteristics, isolation and internalization of EVs, and the recent progresses in the strategies and methodologies of modified EVs for effective cargo-loading is presented. The potential theranostics applications of EVs in brain diseases are further discussed by presenting representative examples. The challenges and obstacles of current studies are also presented, and perspectives for successful clinical translation are further discussed.