Effect of GNPs on human non-cancer breast cells. HuMEC were treated with vehicle, small gold nanospheres (small spheres), nanoflowers (flowers), or big gold nanospheres (big spheres) and analyzed as described for Fig. 2. Nuclei were visualized with DAPI; size bar is 20 μm. Fluorescence intensities/area were quantified for at least 106 nucleoli (a minimum of 52 cells) for each data point and experiment. Bar graphs show the average + STDEV of two independent experiments. V vehicle, S small gold nanospheres, F gold nanoflowers, B big gold nanospheres. Results are normalized to vehicle-treated controls