Fig. 1

A. MSC surface marker expression analysis by flow cytometry. B. (a) Fifth-generation hUC-MSCs under a light microscope; (b and c) osteogenic and adipogenic differentiation of hUC-MSCs; (d) cartilage formation differentiation of hUC-MSCs. C. The vesicle diameter, number, purity, and morphology were tested by electrophoresis (red box, left panel) and Brownian motion video analysis laser scattering microscopy (right panel). D. Western blot detection of the expression of TS101, CD63, CD9, and GAPDH in hUC-MSC-derived exosomes. The negative control was the product extracted from the control medium (CM) according to exosome extraction steps. Full-length blots are presented in Additional file 1: Fig. S1. E. Transmission electron micrographs of hUC-MSC exosomes. Scale bar = 200 nm