Toxicity assessment of aggregated/agglomerated cerium oxide nanoparticles in an in vitro 3D airway model: the influence of mucociliary clearance.

•Testing local defense efficiently predicts local toxicity of particulate matter.•3D airway models with mucociliary apparatus can test local mechanical defense.•Exposure via immersion to cell lines overestimate toxicity of particulate matter.•Nano CeO2 has low toxicity for ciliated epithelium, despite expected deposition.•3D airway models can help reduce the need for animal models in toxicity assessments.