Zinc Oxide nanoparticles cytotoxicity and uptake mechanisms in different cells lines

Abstract

The wide scale use of zinc oxide nanoparticles (ZnO NPs) in the world consumer market makes human beings more prone to the exposure to ZnO nanoparticles and its adverse effects. Zinc oxide nanomaterials are of particular concern because dissolution leads to release of the toxic divalent zinc ions. In this study, the potential cytotoxicity of ZnO NPs (20 nm) at various concentrations has been investigated using three different cell lines: Chinese hamster ovary (CHO) cells, human breast carcinoma (MX-1) cells and rabbit myogenic stem (Fr-1) cells. The cytotoxicity of ZnO NPs was evaluated using the MTT assay. The aim of this study was to compare the cytotoxicity of plain ZnO NPs and ZnO NPs coated with bovine serum albumin (ZnO-BSA NPs) and to find out the impact of NPs processing and internalization pathways on NPs cytotoxicity using various inhibitors. Furthermore, the potential cytotoxic effect of divalent zinc ions was evaluated using ZnSO4 solutions at zinc ion concentrations equivalent to ZnO NPs concentrations at full dissolution. The results showed that ZnO NPs at concentrations varying from 10 to 250 μg/ml had negative concentration-dependent effect on CHO cells. At concentrations higher than 100 μg/ml, ZnO NPs decreased the viability of the tested cells down to 70%. However, the same study with MX-1 and Fr-1 cells led to different results; ZnO NPs increased MX-1 cells viability at all concentrations with the highest increase (35%) increase at 150 μg/ml. Results with FR-1 cells showed concentration-dependant decrease of cell viability with down to 72% viability at 150 μg/ml ZnO NPs, however no cytotoxic effects were observed with the highest ZnO NPs concentrations (200 and 250 μg/ml). Albumin coating decreased ZnO NP cytotoxicity to all three cell types.[...]