Fig. 4

Cell viability ATP assays of CAL-33 spheroids after 24 h incubation. a Cytotoxic effects (dark toxicity) of empty Lipidots with an equalized amount of lipid content as in b. b Cytotoxic effects (dark toxicity) of 3.67 µM (1), 7.34 µM (2) and 14.69 µM (3) mTHPC or 50/120 nm M-Lipidots. **p < 0.01. ***p < 0.001