Ag – ZnO Nanocomposites Cause Cytotoxicity and Induce Cell Cycle Arrest in Human Gastric and Melanoma Cancer Cells

Zinc oxide nanoparticles are used increasingly as antimicrobial and therapeutic agents, and the addition of metal ions such as silver may improve their potent cytotoxicity. However, there have been concerns about safety. In this work, we investigated the cytotoxic activity of newly synthesized silver/zinc oxide nanocomposites (Ag-ZnO NCs) versus ZnO nanoparticles (NPs) against human melanoma (A375) and gastric carcinoma (AGS). The cytotoxicity of Ag-ZnO NCs versus ZnO NPs was evaluated by cell viability assays and the cell cycle analyses were performed by flow cytometry using DAPI staining. Both ZnO NPs and Ag-ZnO NCs significantly reduced cell viability in a dose-dependent manner. We found that Ag-ZnO NCs cytotoxicity was lower than that of ZnO NPs in the same concentration range. Furthermore, the cytotoxicity caused by Ag-ZnO NCs and ZnO induced the accumulation of melanoma cells in S phase and gastric cancer cells in G2/M phase. It was concluded that Ag-ZnO NCs were less toxic than ZnO NPs. This approach provides a rational basis for evaluating the potential harm of ZnO NPs and Ag-ZnO NCs as food packaging materials and cancer therapy agents.