In the evolving field of Mesenchymal Stromal Cell-derived Extracellular Vesicles (MSC-EVs), ensuring consistent quality and therapeutic efficacy remains a challenge due to the complexity of EV biology and production variability. Our research advances the field by leveraging Imaging Flow Cytometry (IFCM) for an unprecedented level of quality control in MSC-EV production. This novel approach allows the direct analysis of EVs in conditioned media, bypassing the need for complex isolation steps, thus enabling real-time, in-process monitoring.

Central to our innovation is the detailed analysis of EV subpopulations using both, ubiquitous EV markers (CD9, CD63, CD81) and those specific to the MSC or human platelet lysate (hPL) environment (CD41, CD61, CD235a), alongside MSC-specific markers (CD90, CD105). This dual-focus analysis permits the development of a detailed 'fingerprint' for MSC-EVs, facilitating the identification of batch inconsistencies and the evaluation of hPL quality.

By comparing these 'fingerprints,' our method not only ensures batch-to-batch consistency but also opens new avenues for monitoring and enhancing the quality of MSC-EV production.

This approach represents a significant step forward in the standardization of MSC-EV therapies, potentially accelerating their transition from bench to bedside and highlighting the role of our method in advancing personalized and regenerative medicine.

BG is a member of a scientific advisory board of Innovex Theraoeutics SL, Mursla Ltd, ReNeuron Ltd and PL BIoscience. He is a founding director of Exosla Ltd. All other authors declare no conflicts of interest.