Synergistic effect of simonkolleite with zinc oxide: Physico-chemical properties and cytotoxicity in breast cancer cells

Zinc Oxide (ZnO) and simonkolleite (SM) have been extensively studied separately in several technological applications. However, the cytotoxicity of SM has not yet been investigated, nor has the synergism between SM and ZnO. In this work, we investigated both the synergism of SM with ZnO in the physico-chemical properties and cytotoxicity in breast cancer cells. The physical characterization confirmed that with the increase of the annealing temperature, the transformation of SM into ZnO occurs and further investigated how photocatalytic performance and cytotoxicity were changed. The photocatalytic performance of ZnO was the highest (80%) in contrast to SM and the SM/ZnO nanocomposite (NCT), had no photocatalytic activity. Cytotoxicity was investigated using the MCF-10A, MCF-7, and MDA-MB-231 tumor cell lines. SM resulted in a high incidence of cell death at a high concentration and induced the production of reactive oxygen species at a low concentration. ZnO and NCT were observed to have the expected effect regarding cytotoxicity, and the induction of reactive oxygen species was much higher than with SM. The biological ROS results were in excellent agreement with the photocatalytic performance, demonstrating that the mechanism of the antitumor effect of SM does not occur predominantly via ROS. Therefore, in this work, we demonstrate how the physico-chemical and biological properties are changed due to the synergism of SM and ZnO.