Figure 1. Identification of exosomes from Human umbilical cord derived mesenchymal stem cells (HUMSCs). (A) Observation of the shape and size of exosomes by transmission electron microscopy. (B) Measurement of the size of exosomes by dynamic light scattering. (C) Zeta potential of the exosomes. (D) The expression of CD9 and CD63, the surface markers of exosomes by Western blot.