Figure 1. Characterization of exosomes released by adipose-derived mesenchymal stem cells (ADSCs). (A) ADSCs showed a typical cobblestone-like morphology. Scale bar: 30 μm. (B–G) Immunofluorescence staining of cell surface markers. The antibodies were labeled with fluorescein isothiocyanate (FITC, green). CD29, CD90, CD44, and CD105 were positive. The von Willebrand Factor was negative. FITC- and PE-labeled mouse IgG isotype controls are shown (magnification: 200×). Scale bar: 30 μm. (H, I) Differentiation potential of ADSCs assessed by Oil Red O (H) and alkaline phosphatase staining (I). Scale bar: 50 μm. (J) Western blots of CD63 and CD9 expressions in exosomes from hypoxia-pretreated or wild-type ADSCs. (K) Transmission electron micrographs showing ADSC-exosome morphology. Scale bar: 100 nm. (L) Particle size distribution and concentration of ADSC-exosomes measured by nanoparticle tracking analysis.