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

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.