Theranostic extracellular vesicles: a concise review of current imaging technologies and labeling strategies

Abstract

Extracellular vesicles (EVs), or exosomes, are naturally occurring nano- and micro-sized membrane vesicles playing an essential role in cell-to-cell communication. There is a recent increasing interest in harnessing the therapeutic potential of these natural nanoparticles to develop cell-free regenerative medicine and manufacture highly biocompatible and targeted drug and gene delivery vectors, amongst other applications. In the context of developing novel and effective EV-based therapy, imaging tools are of paramount importance as they can be used to not only elucidate the underlying mechanisms but also provide the basis for optimization and clinical translation. In this review, recent efforts and knowledge advances on EV-based therapies have been briefly introduced, followed by an outline of currently available labeling strategies by which EVs can be conjugated with various imaging agents and/or therapeutic drugs and genes. A comprehensive review of prevailing EV imaging technologies is then presented along with examples and applications, with emphasis on imaging probes and agents, corresponding labeling methods, and the pros and cons of each imaging modality. Finally, the potential of theranostic EVs as a powerful new weapon in the arsenal of regenerative medicine and nanomedicine is summarized and envisioned.

New insights of engineered extracellular vesicles as promising therapeutic systems

“…Recent advances in the therapy of ocular diseases based on MSC-EVs are demonstrated, and the associated challenges and prospects are discussed as well. Shinge et al (2022) presented an overview of the identified roles of plant exosome-like nanovesicles (PELNVs) in physiology and pathology [11] . They also provided new insight toward the engineering of the plant-originated EV for effective therapeutics besides the bacteria and mammalian cell, pointing out a clue for future direction to the ongoing research gaps.…”

“…The final review article by Aafreen et al (2023) introduces recent efforts and knowledge advances in EVbased therapies [12] . They also outline currently available labeling strategies by which EVs can be combined with various imaging agents and/or therapeutic drugs and genes.…”

Exploring the Biogenesis of Extracellular Vesicles in Cancer and Stem Cell Biology: Diverge Origins, Common Threads

“…Exosome biogenesis is of particular interest as these sEVs have emerged as pivotal mediators for orchestrating intercellular signalling in physiological and pathological states 8,9 . Clinically, sEVs have gained signi cant importance in terms of theranostics [10][11][12][13] . Cancer cells employ exosomes to promote malignancy, and can be used as biomarkers, while stem cells utilize exosomes for regenerative functions 10,14 .…”