Fig. 4

The uptake of GO in IECs induced dose- and time-dependent toxicity based on cell viability and LDH release. a The uptake of GO in FHC cells following 50 µg/mL GO treatment for 24 h. The red arrows indicate GO accumulation in the cytoplasm under TEM observation. Scale bar: 1 μm. b, c GO was labeled by FITC-BSA and exposed to FHC cells for additional 24 h. Untreated cells were served as control group, while single FITC-BSA exposed to FHC cells was included as negative control group. The green fluorescence of FITC-BSA labeled GO on the cytoplasm and cytomembrane of FHC cells using confocal microscopy. Scale bar: 20 μm. The relative fluorescence intensity was measured using flow cytometry. d, e Relative cell viability and LDH release in cultured FHC cells incubated with GO at different concentrations (0, 10, 25, 50, 100, or 200 µg/mL) for 24 h, or 25 and 50 µg/mL GO for 6, 12, and 24 h. The results were expressed as means ± SEMs  from three independent experiments. *P < 0.05, **P < 0.01