Screening of different metal oxide nanoparticles reveals selective toxicity and inflammatory potential of silica nanoparticles in lung epithelial cells and macrophages

Abstract

In cell culture studies, foetal calf serum (FCS) comprising numerous different proteins is added, which might coat the surface of engineered nanomaterials (ENMs) and thus could profoundly alter their biological activities. In this study, a panel of industrially most relevant metal oxide nanoparticles (NPs) was screened for toxic effects in A549 lung epithelial cells and RAW264.7 macrophages in the presence and absence of FCS. In medium without FCS amorphous SiO₂-NPs were the most cytotoxic NPs and induced a significant pro-inflammatory response in both cell types. An increased anti-oxidative response after exposure to SiO₂-NPs was, however, only observed in RAW264.7 macrophages. Furthermore, pre-coating of SiO₂-NPs with FCS proteins or simply bovine serum albumin abrogated responses in A549 lung epithelial cells. Thus, the protein corona bound to the surface of SiO₂-NPs suppresses their biological effects, an issue which needs to be more carefully considered for in vitro–in vivo extrapolations.

Keywords::

• Nanoparticle toxicity
• silica
• metal oxide
• inflammation
• protein corona

Acknowledgments

We thank Silvia Andraschko, Tamara Walther, Anika Wagner, Maximilian Kohnle, Marco Mackert, Manuela Hauser and Deniz Akten for their excellent technical assistance. The study was supported by the priority programme SPP1313 of the German Research Foundation (DFG) within the cluster NanoSyncc (DFG grant WE 291816-1).