In vitro Acute Toxicity of Metal-Based Nanoparticles in Human Trophoblast BeWo b30 Cells

Abstract

Metal nanoparticles (M-NP) are among the most widely used nanomaterials in consumer products available in the market. Thus, human exposure to these nanosized materials is increasing, which raises serious concerns regarding their environmental and human safety. Biological barriers are important lines of defence to xenobiotics, thus expected targets for M-NP. In this regard, special consideration must be given to the placenta that acts as barrier between maternal and the developing fetus. The present study aimed at evaluating in vitro toxicity of different M-NP in a human cell model of placental barrier: trophoblastic (BeWo clone b30) epithelial cells. BeWo b30 cells were exposed for 24 h to varied concentrations (0.8 – 48 μg/cm 2) of M-NP of different chemical composition (Au, Ag and TiO2), primary size (10, 30 and 60 nm), capping (citrate and PEG) and crystal structure (rutile and anatase). In vitro toxicity was assessed by determining changes in cell morphology, metabolic activity, plasma membrane integrity, generation of intracellular reactive oxygen species (ROS) and ATP intracellular levels. The tested M-NP can be ranked for their in vitro toxicity potential with AgNPs > AuNPs > TiO2 NPs, being the effects more visible at higher concentrations. No significant changes in cell morphology following exposure to all tested M-NP were detected. The influence of the size in the cytotoxic-induced effects was more evident for AgNP than for AuNP, with the smaller NP causing more toxicity. In addition, PEG-capping effectively attenuated AuNP-induced toxicity. Only cells exposed to AgNP exhibited a significant increase in ROS levels. All tested M-NP significantly increased intracellular ATP levels compared to control cells, with the exception of AuNP 10 nm. Thus, our data support that the physicochemical properties of M-NP are an important determinant of their cytotoxicity in BeWo b30 cells. Future studies will be useful to further explore the effects of M-NP in the placental barrier.