TP53 and osteosarcoma: HOS (p53-expressing) and Saos-2 (p53-deficient) osteosarcoma cell viability was assessed by the MTT assay, for two different AgNP sizes (7 and 60 nm) and six different concentrations (c1 = 10 ppm, c2 = 5 ppm, c3 = 2.5 ppm, c4 = 1.25 ppm, c5 = 0.625 ppm, and c6 = 0.3125 ppm), at three time points (24 hours, 48 hours, and 72 hours).