Lars B. Leibrock 1, Harald Jungnickel 1, Jutta Tentschert 1, Aaron Katz 1, Blaza Toman 2 , Elijah J. Petersen 3 , Frank S. Bierkandt 1, Ajay Vikram Singh 1 , Peter Laux 1 and Andreas Luch 1
1 German Federal Institute for Risk Assessment (BfR), Department of Chemical and Product Safety, Max-Dohrn-Strasse 8-10, 10589 Berlin, Germany;
2 Information Technology Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaitherburg, MD 20899-8311, USA;
3 Materials Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaitherburg, MD 20899-8311, USA;
ALI systems are considered to be a promising exposure system to study toxicological e ects of airborne nanomaterials instead of in vivo inhalation studies and have been widely used to assess the toxicology of nanomaterials in recent years. However, the robustness of these methods is not yet wellunderstood. Here we reported a C&E analysis of a commonly used flow through ALI exposure system.
Air–liquid interface (ALI) systems have been widely used in recent years to investigate the inhalation toxicity of many gaseous compounds, chemicals, and nanomaterials and represent an emerging and promising in vitro method to supplement in vivo studies. ALI exposure reflects the physiological conditions of the deep lung more closely to subacute in vivo inhalation scenarios compared to submerged exposure. The comparability of the toxicological results obtained from in vivo and in vitro inhalation data is still challenging. The robustness of ALI exposure scenarios is not yet well understood, but critical for the potential standardization of these methods. We report a cause-and-effect (C&E) analysis of a flow through ALI exposure system. The influence of five different instrumental and physiological parameters affecting cell viability and exposure parameters of a human lung cell line in vitro (exposure duration, relative humidity, temperature, CO2 concentration and flow rate) was investigated. After exposing lung epithelia cells to a CeO2 nanoparticle (NP) aerosol, intracellular CeO2 concentrations reached values similar to those found in a recent subacute rat inhalation study in vivo. This is the first study showing that the NP concentration reached in vitro using a flow through ALI system were the same as those in an in vivo study.