Figure 4.

Cell viability of HepG2 spheroids.

Notes: Spheroids were stained with FDA (green) as viable marker and PI (red) as necrosis marker. Representative images of untreated cell spheroid (A), spheroid exposed to 100 µg mL⁻¹ SiO₂ NPs for 24 hours (B), and spheroid exposed to 1% triton X-100 for 1 hour (C) are shown. Beside the transmission image, the fluorescence images of the FDA and PI as well as the merged image of all channels are presented.

Abbreviations: FDA, fluorescein diacetate; NPs, nanoparticles; PI, propidium iodide.