Fig. 1

Identification and characterization of exosomes. a Representative transmission electron microscopy image of MCF-7 and MCF-7/ADR derived exosomes, showing a typical “saucer-like” morphology and a diameter of 30–100 nm (scale bar, 100 nm). b and c Analysis of exosome size indicated similar particle size distribution of exosomes secreted by MCF-7 and MCF-7/ADR (mean ± SD). d  Exosome purity as assessed by western blot analysis for the expression of the exosomal marker CD63, TSG101 and endoplasmic reticulum protein calnexin. P-gp in total cellular protein and corresponding exosomes of MCF-7 and MCF-7/ADR cells were also detected