Cytotoxic effects of green zinc oxide nanoparticles in colon cancer(ht-29) and normal cell line (huvec)

Among a variety of nanoparticles, zinc oxide nanoparticles (ZnO-NPs) have advantages because of the extraordinary physical and chemical properties. It is one of the important materials in cosmetic industry, nano-fertilizers, and electrical devices and also a suitable agent for bio-imaging and targeted drug and gene delivery and an excellent sensor for detecting ecological pollutants and environmentalremediation. Yet information regarding their action in cells is incomplete and there are conflicting reports about in vitro cytotoxicity. The purpose of this study was to examine the cytotoxic effects of ZnO-NPs biosynthesized with Hyssopus officinalis extract (ZnO-NPs/Hf) on colon cancer cells (HT- 29) and normal cells (Huvec) . Two cell lines including cancer cells (HT-29) and normal cells (Huvec) were used to evaluate the cytotoxicity of the ZnO-NPs/Hf. To perform the MTT assay the cells were cultured in a flat-bottomed cell culture plates and placed in an incubator for 24 h. After taking thenecessary time, the medium was carefully removed and to all the wells were added treatment medium including 31.2, 62.5, 125, and 250 μg/ml of ZnO-NPs/Hf. after 24h, The MTT solution was added toeach well and 4 h later the discharge MTT solution and 100 μl of DMSO were added and eventually the absorption was evaluated. Statistical analysis of the results showed that during incubation period, thepercentage of cell viability was reduced by increasing the dose. As a result, the percentage of viability of HT-29 cells was reduced from 69.09 % at a concentration of 30 μg / ml to 25.85% at a concentrationof 250 μg / ml that difference was statistically significant (P≤0.001). Results showed the percentage of viability of Huvec cells was reduced from 94.9 % to 59.72 % at the same concentrations. The comparison of cytotoxicity levels suggests that the Zn O-NPs/Hf inhibits cancerous cells in low concentrations (IC50: 60μg/ml) , while not affecting on normal cells in same dose. Zinc oxide nanoparticles biosynthesized with Hyssopus officinalis extract have the ability to induce apoptosis in cancer cells in dose depended manner but no effects on normal cells. Thus this green nanoparticle can be considered as a new promising and effective strategy for the treatment of colon cancer.