Recent advances in microfluidic approaches for the isolation and detection of exosomes

Exosomes are nano-sized extracellular vesicles secreted by most types of cells which facilitate intercellular communication by delivering molecular cargoes (e.g., nucleic acids and proteins) from donor cells to recipients. Due to their roles as vehicles for cell-to-cell transport, exosomes have garnered a great deal of scientific attention as diagnostic biomarkers for various diseases. However, currently available techniques for exosome isolation, including ultracentrifugation and membrane filtration, lack the sensitivity and specificity required to effectively separate exosomes from other similarly sized biomolecules in body fluids. To overcome these challenges, various microfluidic devices have been developed to improve the purity and yield of isolated exosomes, reduce processing times, and increase throughputs. This paper provides a comprehensive overview of microfluidic devices used to isolate, detect, and analyze exosomes from body fluids with emphasis on their designs and working principles from an analytical perspective. Specifically, we outline recent progress made in the design of microfluidic-based exosome isolation devices. In addition, we highlight challenges posed by the clinical translation of these devices and their potentials and offer guidelines to engineers and clinicians interested in this field.