Fig. 2

C6 glioma cells were seeded onto 35-mm glass bottom dishes and the cells were incubated with 5 nm, 13 nm, 30 nm or 120 nm AuNP-S-mPEG for 24 h. The intracellular uptake of these nanoparticles was examined using reflectance imaging. In each image, the leftmost section shows the bright field image of the cells, the second section shows the reflectance image of the particles taken up by the cells, the third section shows the fluorescent Hoechst staining for DNA, and the rightmost section shows the fused image. The C6 glioma cells were incubated with AuNP-S-mPEG with the following sizes and mass concentrations: (A) 5 nm and 12.7 mg/L, (B) 5 nm and 138.4 mg/L, (C) 13 nm and 6.9 mg/L, (D) 13 nm and 68.6 mg/L, (E) 30 nm and 8.7 mg/L, (F) 30 nm and 51.6 mg/L, and (G) 120 nm and 33.6 mg/L. The mass concentrations in (A), (C), (E), and (G) were almost the same as those of 1-MBq ²¹¹At-AuNP-S-mPEG in the cytotoxicity studies (A), (B), (C), and (D) illustrated in Fig. 1, respectively (see Additional file 1: Table S3)