Abstract
Background: Exosomes derived from mesenchymal stem cells (MSCs) are of considerable interest for regenerative medicine; however, their application is limited by the lack of standardized and reproducible isolation methods. Objective: To compare the efficiency of an experimental kit and a commercial kit for exosome isolation from the conditioned medium of human umbilical cord-derived MSCs. Methods: Exosomes were isolated from conditioned medium collected from MSCs at passages 4 and 10 and from different medium volumes (1, 5, and 9 mL). Particle size and zeta potential were determined by particle tracking analysis, while total protein concentration was measured using the Bradford assay. Results: Both kits enabled the isolation of vesicles of comparable size characteristic of exosomes (161.4–177.9 nm). The commercial kit provided a higher protein yield, whereas the experimental kit differed in the magnitude and polarity of the zeta potential. For both methods, the yield decreased at later MSC passages and increased with larger volumes of conditioned medium. Conclusion: The experimental kit provides isolation of exosome-like extracellular vesicles comparable to that obtained with the commercial kit and may be considered a promising alternative, provided that additional assessment of preparation purity and molecular markers is performed.