Fig. 3

MALDI-MSI images of a coronal section of rat brain tissue and the density of rGO in the brain. The rats received a single dose (7 mg/kg) of rGO via tail vein and were killed at a 15 min, b 1 h, c 3 h and d 7 days after administration. e Representative distribution of m/z 465 signal in control animals; the central black dashed line delineates the hippocampus boundaries. The color scale shows the ion intensity of the rGO (blue color for the lowest signal and yellow/red color for highest). The evaluation in arbitrary units (a.u.) of pixels intensity (shown in f) was normalized by discounting the matrix background. f Quantification of rGO in brain at different times after administration. The columns represent the mean ± SEM (n = 3 images/interval; one image per animal). *p < 0.05 and ***p < 0.001 compared to the corresponding control. ^##p < 0.01 and ^###p < 0.001 between rGO-treated time-points (one-way ANOVA followed by the Bonferroni post hoc test)