Since we identified AgNPs of smaller and bigger sizes on the cell surface and in the cytoplasm as well (Fig. 3), but detected no particles within mitochondria and nuclei, it can be hypothesised that silver ions released from the nanoparticles are responsible for the observed mitochondrial stress in both p53-expressing and in p53-deficient osteosarcoma cells. This evidence concerns the gene TP53 and osteosarcoma.