Characterization of human induced pluripotent stem cell-derived mesenchymal stem cells (hiPSC-MSCs) and hiPSC-MSC-derived exosomes (hiPSC-MSC-Exos). (A) Light microscopy images demonstrating morphological changes occurring during hiPSCs differentiation into fibroblast-like cells. (a) Representative cell morphology of hiPSCs before differentiation. (b) Intermediate phase of differentiating the hiPSCs into MSCs. (c) Typical fibroblast-like morphology of cells. (B) Flow cytometric analysis of the surface markers in hiPSC-MSCs. (C) Assessment of the tri-lineage differentiation capacity of iPSC-MSC-like cells. (a) Alizarin Red staining for osteocytes after 3 weeks in culture with osteogenic medium. (b) Alcian Blue staining for chondrocytes after 4 weeks in culture with chondrogenic medium. (c) Oil Red O staining for adipocytes after 2 weeks in culture with adipogenic medium. The qRT-PCR results for OCN (d), Sox9 (e), and LPL (f) after 7 days in culture with osteo-, chondro-, and adipogenic mediun. (D) Transmission electron microscope images of hiPSC-MSC-Exos morphology. Scale bars = 100 nm and 50 nm, respectively. (E) Detection of CD9, CD63, and CD81 incorporation into hiPSC-MSC-Exos by western blotting.