Zirconia Nanoparticles-Induced Toxic Effects in Osteoblast-Like 3T3-E1 Cells

Mingfu Ye,Bin Shi

doi:10.1186/s11671-018-2747-3

Abstract

Zirconia (ZrO2) is one of the widely used metal oxides for potential bio-applications such as biosensors, cancer therapy, implants, and dentistry due to its high mechanical strength and less toxicity. Because of their widespread applications, the potential exposure to these nanoparticles (NPs) has increased, which has attracted extensive attention. Thus, it is urgent to investigate the toxicological profile of ZrO2 NPs. Titanium dioxide (TiO2) is another extensively used nanomaterials which are known to be weakly toxic. In this study, TiO2 NPs were served as control to evaluate the biocompatibility of ZrO2 NPs. We detected the cytotoxicity of TiO2 and ZrO2 NPs in osteoblast-like 3T3-E1 cells and found that reactive oxygen species (ROS) played a crucial role in the TiO2 and ZrO2 NP-induced cytotoxicity with concentration-dependent manner. We also showed TiO2 and ZrO2 NPs could induce apoptosis and morphology changes after culturing with 3T3-E1 cells at high concentrations. Moreover, TiO2 and ZrO2 NPs at high concentrations could inhibit cell osteogenic differentiation, compared to those at low concentrations. In conclusion, TiO2 and ZrO2 NPs could induce cytotoxic responses in vitro in a concentration-dependent manner, which may also affect osteogenesis; ZrO2 NPs showed more potent toxic effects than TiO2 NPs.

Highlights

During the past few decades, the application of engineered nanoparticles (NPs) has expanded in various fields, such as electronics, biomedical applications, and pharmaceuticals
To measure the size of Titanium dioxide (TiO2) NPs and ZrO2 NPs in solution, dynamic light scattering (DLS) was used and the particles of TiO2 NPs and ZrO2 NPs expanded to 81.2 nm and 93.1 nm, respectively, which indicated an agglomeration effect
The zeta potentials of TiO2 NPs and ZrO2 NPs were 32.9 ± 5.4 mV and 42.4 ± 7.4 mV, respectively

Summary

Introduction

During the past few decades, the application of engineered nanoparticles (NPs) has expanded in various fields, such as electronics, biomedical applications, and pharmaceuticals. Zirconia (ZrO2) NPs are one of the major nanomaterials used for synthesizing refractories, foundry sands, and ceramics. Toxicological studies on ZrO2 NPs are limited, and the results were controversial. Some studies have reported that ZrO2 NPs showed better biocompatibility when compared with other nanomaterials, including ferric oxide, titanium dioxide (TiO2), and zinc oxide (ZnO) [3–6]. In agreement with these results, others have reported ZrO2 NP could induce mild [3, 7] or no cytotoxic effects [8–10], and only few studies indicated a mild cytotoxic potential. In this study, we evaluated the cytotoxic effects of ZrO2 NPs, providing useful insight for their future application in vivo. We treated the cells with TiO2 NPs as the control group, which toxicological profile has been well developed [13]

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