Fig. 2

MSC viability in response to treatment with PLGA-PEI PCS NPs (+) and observation of NP internalization. Exosome expression was also observed according to internalization of PLGA-PEI PCS NPs. a Cell viability of MSCs treated with 2, 5, 10, 20, 40, and 60 μg/mL PCS NPs. b Cell viability of MSCs treated with PCS NPs during exposure for 1, 2, 4, 6, and 24 h. c Images of MSCs incubated with 0, 5, 10, and 20 μg/mL PCS NPs using fluorescent microscopy. d TEM images of PCS NPs and extracellular vesicles (exosomes and macrovesicles) in MSCs. The blue arrows depict PCS NPs and the red arrows depict extracellular vesicles. e The release of exosomal marker CD63 by the MSCs in media. f Identification of exosomal markers CD63, CD9, and CD81 released by the MSCs in media as determined by Western blot. g Quantification of expression levels of exosomal markers released by the MSCs. Data are mean ± SD. *p < 0.05, ***p < 0.001