Fig. 2. Nanodiamond uptake observed in MCF-7 cells. Cells were incubated with 1 μg mL^–1 graphitic or oxidized nanodiamonds for 1, 2, 4, 8, 24 and 48 hours before fixation. Cells were then co-stained with NucBlue nuclear stain and membrane stain Wheat Germ Agglutinin-Alexa Fluor 488. Nanodiamond scattering signal was detected at 633 nm. An increase in the number of nanodiamonds within cells may be observed over time up to 48 h (white arrows denote dense cellular uptake).