Manufactured silver and gold nanoparticles-induced apoptosis by caspase-pathway in human cell lines

Metallic nanoparticles have emerged as an important class of nanomaterials for a wide range of industrial and medical applications. Because of the intensive commercial applications, risk assessment of these nanoparticles is of great importance. In the present study, the human hepatoma and leukemia cells were used to characterize the apoptotic effects of silver nanoparticles (4.7 and 42nm) and gold nanoparticles (30nm). Apoptotic cells were identified by chromatin condensation and flow cytometry analysis, using Annexin V/PI, TUNEL and caspase activation assays. Flow cytometry analysis showed that the three metallic nanoparticles induced apoptotic cell death in a concentration and time dependent-manner. Moreover, the three nanoparticles induced activation of caspase-3 and -7 in hepatoma and leukemia cells. Apoptotic effects were stronger after exposure of both cell lines with 4.7nm silver nanoparticles than those obtained with 42nm silver and 30nm gold nanoparticles. In conclusion, silver (4.7 and 42nm) and gold (30nm) nanoparticles induced apoptosis in hepatoma and leukemia cells via the caspase dependent pathway. The smaller silver nanoparticles (4.7nm) had a greater ability to induce apoptosis in both cell lines.