Fig. 2

Characterization of human C-EVs. a The morphology of chondrocytes was observed using haematoxylin–eosin staining. Scale bar = 500 μm. b The morphology of C-EVs was analysed by transmission electron microscopy. Scale bar = 200 nm. c The particle size distribution of C-EVs was measured using a flow nano analyser. d The expression of CD9 and CD63 in C-EVs was measured using a flow nano analyser. e Western blotting analysis of the protein levels of CD63, CD9, TSG101, and calnexin in C-EVs and chondrocytes. f The representative immunofluorescence photomicrograph for cellular uptake of FITC-labelled C-EVs (green) was obtained using confocal microscopy. Scale bar = 50 μm