Fig. 6

A Cytotoxicity test of NPs on HT-29 spheroids. Spheroids were left untreated (control) or treated with different concentrations of targeted YSA-L-ZnO or with the untargeted control NPs (L-ZnO). After 24, 48, 72 and 96 h from the exposure, spheroids were disaggregated, dead cells were stained with propidium iodide, and the viability was measured through flow cytometry. Data are normalized by the control sample, which is considered to be 100% vital. B Live-cell fluorescence microscopy images of the spheroids treated with YSA-L-ZnO at different concentrations and time steps. Spheroids were stained with Calcein AM (green channel) and Propidium Iodide (red channel) to mark the live and the dead cells respectively; cell nuclei were also stained with Hoechst (blue channel). C) Flow cytometry results of internalization test on HT-29 spheroids. *p < 0.0332, **p < 0.0021, ***p < 0.0002, ****p < 0.0001