Fig. 7

N-GQDs induced iron overload through calcium-iron crosstalk mediated by L-VGCCs in BV2 cells. a Representative fluorescent images of intracellular ferrous iron level in BV2 cells showed orange using FerroOrange dye. The nucleus showed blue using DAPI, Scale bar: 20 µm; b representative fluorescent images of intracellular calcium level in BV2 cells showed green using Fluo4 dye with HBSS containing calcium and magnesium. The nucleus showed blue using DAPI, Scale bar: 20 µm; c the protein expression of CACNA1D in BV2 cells using western blotting analysis; d, e representative FITC fluorescence histogram plot of BV2 cells showed cytosolic ROS production using DCFH-DA dye, and the quantitative results of mean fluorescence intensity (MFI). BV2 cells were pre-treated with nifedipine, diltiazem, verapamil and DFOM for 2 h and then exposed to 100 µg/mL N-GQDs for 24 h (n = 3). Data are showed as mean ± SD of three independent experiments. The one-way ANOVA followed by the Dunnett’s t test were used to determine statistical significance (*P < 0.05, **P < 0.01, ***P < 0.001 vs. the control or 100 µg/mL N-GQDs)