Fig. 11. Apoptotic mechanism of HEp-2 cells treated with pcAgNPs. DNA fragmentation of HEp-2 cells exposed to pcAgNPs (a). RT-PCR analysis of p53 expression, leading to apoptotic cell death (b and c); pcAgNP activation of p53, leading to increased catalase expression. HEp-2 cells treated with 15 μg mL⁻¹ pcAgNPs for 24 h, showing p53, p21 and catalase expressions assessed using Western blotting analysis. β-actin served as a loading control. Numbers were calculated by quantitative densitometric analysis and indicate the ratio of specific proteins versus β-actin. (d) Data are representative of at least three independent experiments.