Figure 2.

Identification of human USC exosomes (USCs-exos). (a) Human USCs exhibit a short fusiform or spindle-shaped appearance, with sporadic cells appearing on day three (left picture) and large numbers of cells appearing at day seven (right picture). (b) Osteogenic, adipogenic, and chondrogenic differentiation capabilities of USCs were determined by Alizarin Red, Oil Red O, and Alcian Blue staining. (c) USC surface markers (CD29, CD44, and CD73) were detected by flow cytometry. (d) A typical image of USCs-exos morphology as obtained by a transmission electron microscope (TEM). (e) Particle size distribution of USCs-exos as determined by the nanoparticle size analysis. (f) The protein marker of USCs-exos as detected in exosomes and USCs by Western blot analysis. (g) Exosomes taken by NP cells incubated with PKH26-labeled USCs-exos for 12 hours, and NP cell nuclei were stained with DAPI.