Fig. 1

Graphene oxide influences the phenotypic properties and morphology of U87 GSCs. a U87 cells were cultured in a serum-free environment for 2–7 days. Sphere morphology was photographed using light microscopy. Scale bar = 100 μm. b The expression of SOX2, CD133 and OCT4 in glioblastoma stem-like cells was increased during different periods. c Morphological appearance of GSCs with or without GO treatment after 2 days. The GSC spheres subject to GO treatment showed adherent growth and some transformed to fusiform cells. Left: scale bar = 50 μm; right: scale bar = 20 μm. d The number of large GSC spheres (diameters larger than 50 μm) declined as the concentration of GO increased. The panel shows the number of spheres that were larger than 50 μm in different groups. The concentrations of GO were 5, 12.5, 25, 50 μg/ml. GSCs were counted in 5 random fields and data are expressed as mean ± SEM. *p < 0.05, **p < 0.01. Data represent the mean ± SEM of at least three independent experiments