Abstract
Owing to the wide use of novel nanoparticles (NPs) such as zinc oxide (ZnO) in all aspects of life, toxicological research on ZnO NPs is receiving increasing attention in these days. In this study, the toxicity of ZnO NPs in a human pulmonary adenocarcinoma cell line LTEP-a-2 was tested in vitro. Log-phase cells were exposed to different levels of ZnO NPs for hours, followed by colorimetric cell viability assay using tetrazolium salt and cell survival rate assay using trypan blue dye. Cell morphological changes were observed by Giemsa staining and light microscopy. Apoptosis was detected by using fluorescence microscopy and caspase-3 activity assay. Both intracellular reactive oxygen species (ROS) and reduced glutathione (GSH) were examined by a microplate-reader method. Results showed that ZnO NPs (≥0.01 μg/mL) significantly inhibited proliferation (P < 0.05) and induced substantial apoptosis in LTEP-a-2 cells after 4 h of exposure. The intracellular ROS level rose up to 30–40% corresponding to significant depletion (approximately 70–80%) in GSH content in LTEP-a-2 cells (P < 0.05), suggesting that ZnO NPs induced apoptosis mainly through increased ROS production. This study elucidates the toxicological mechanism of ZnO NPs in human pulmonary adenocarcinoma cells and provides reference data for application of nanomaterials in the environment.
Highlights
IntroductionWith rapid development of nanotechnology, the application field and commercial manufacturing scale of synthetic nanomaterials and nanoparticles (hereinafter referred to as NPs) have undergone significant expansion worldwide
With rapid development of nanotechnology, the application field and commercial manufacturing scale of synthetic nanomaterials and nanoparticles have undergone significant expansion worldwide
Zeta potential data indicate that the zinc oxide (ZnO) NPs have a positive surface charge, −18.6 mV at pH 7.4 in Dulbecco’s modified Eagle’s medium (DMEM) (Figure 1(b)), which is inadequate to stabilize the suspension of ZnO NPs via repulsive force and may cause NPs aggregation in DMEM
Summary
With rapid development of nanotechnology, the application field and commercial manufacturing scale of synthetic nanomaterials and nanoparticles (hereinafter referred to as NPs) have undergone significant expansion worldwide. This situation has increasingly aggravated the damage to ecological environment and human health, mainly because various NPs have diverse effects (small-scale, surface, quantum-size, and/or macroscopic quantum tunneling) [1]. The biological safety of NPs has aroused great concerns by governments and academic circles Metal oxide nanomaterials such as zinc oxide (ZnO) NPs exhibit antibacterial, anticorrosive, antifungal, and UVfiltering properties as well as certain cytotoxicity [1]. Exploring the exact mechanism of this novel nanomaterial is of great value for clinical trials of cancer treatment
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