Fig. 4. Dark-field images of cells incubated with gold nanoparticles and their intracellular LSPR.

a Dark-field images of A549 cancer cells treated with three different types of particles. b Dark-field images of HepG2 cancer cells treated with three different types of particles. Few SBs entered into cells, while nanospheres were found more often in cells. c Spectral responses from different regions of HepG2 cells (nucleus and cytoplasm), gold nanospheres in HepG2 cells, and corrected responses after normalization with respect to the halogen lamp spectrum (right panel). d Spectral responses from different regions of A549 cells (nucleus and cytoplasm), gold nanospheres in A549 cells, and corrected responses after normalization with respect to the halogen lamp spectrum (right panel). The scale bar is 20 µm