ZnO Quantum Dots Induced Oxidative Stress and Apoptosis in HeLa and HEK-293T Cell Lines.

Yanjie Yang,Zhenhua Song,Shaoping Ji,Ao Xu,Shuangyu Lv,Weixia Wu

doi:10.3389/fphar.2020.00131

Abstract

Zinc oxide (ZnO) quantum dot (QD) is a promising inexpensive inorganic nanomaterials, of which potential toxic effects on biological systems and human health should be evaluated before biomedical application. In this study, the cytotoxicity of ZnO QDs was assessed using HeLa cervical cancer cell and HEK-293T human embryonic kidney cell lines. Cell viability was significantly decreased by treatment with 50 µg/ml ZnO QDs after only 6 h, and the cytotoxicity of ZnO QDs was higher in HEK-293T than in HeLa cells. ZnO QDs increased the level of reactive oxygen species and decreased the mitochondria membrane potential in a dose-dependent manner. Several gene expression involved in apoptosis was regulated by ZnO QDs, including bcl-2 gene and caspase. In HeLa cells, ZnO QDs significantly increased early and late apoptosis, but only late apoptosis was affected in HEK-293T cells. These findings will be helpful for future research and application of ZnO QDs in biomedicine.

Highlights

Zinc oxide nanoparticles (ZnO NPs) are one of the most extensively used nanomaterials, due to the unique physicochemical properties and low cost
The average diameter of ZnO quantum dot (QD) was approximately 7.10 ± 0.30 nm according to transmission electron microscopy (TEM, Figure S1) and 7.43 nm from dynamic light scattering (DLS, Figure S2A)
The Cell Counting Kit-8 (CCK-8) assay was used to examine the viability of HeLa and HEK-293T cells after incubation with ZnO QDs (Figure 1)

Summary

Introduction

Zinc oxide nanoparticles (ZnO NPs) are one of the most extensively used nanomaterials, due to the unique physicochemical properties and low cost. ZnO NPs could protect the cells against the ultraviolet (UV)-induced skin damage, and have been applied to cosmetics (Vallabani et al, 2019). ZnO NPs are being explored for biomedical applications, including pharmaceuticals, dental fillings, drug delivery, biosensors, and bioimaging (Kim et al, 2019; Vallabani et al, 2019). ZnO NPs were reported to induce cytotoxicity in a variety of cancer cells, including HepG2, U87, MCF-7 etc. (Roshini et al, 2017) They can accumulate in various internal organs (such as liver, spleen, lungs, kidney, and heart) via circulation and produce adverse consequences (Shen et al, 2019)

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Results

Conclusion