Beyond Extracellular Vesicle (EV) Hype: Practical Solutions and Remaining Hurdles in EV Research, Manufacturing, and Clinical Translation.

Extracellular vesicles (EVs) are nanoscale mediators of intercellular communication with diverse molecular cargoes that reflect their cell of origin. Advances in isolation, detection, and single-particle analytics have revealed increasing molecular and functional heterogeneity, while exposing limitations in how EV identity and activity are currently defined. The field has expanded rapidly; however, translational progress is constrained by an incomplete mechanistic understanding, a lack of standardized measurements, and inconsistencies in regulatory classification. This review provides a critical synthesis of current EV research from an analytical and translational perspective, emphasizing the measurement science needed to define, compare, and benchmark EV preparations as therapeutic products. We discuss evolving regulatory frameworks and recent updates to the MISEV guidelines, highlighting the need for operational definitions grounded in source material, isolation method, and molecular markers. Updated workflow considerations are presented across EV production and characterization, with a focus on orthogonal analyses, quantification of co-isolates, and potency assays that support reproducibility and quality control. Together, these advances and ongoing challenges underscore the need for analytical rigor to transform EV research from descriptive studies into a reproducible and quantitative measurement science.