TiO2 nanoparticles (NPs) are extensively used in various applications, highlighting the importance of ongoing research into their effects. This work belongs among rare whole-body inhalation studies investigating the effects of TiO2 NPs on mice. Unlike previous studies, the concentration of TiO2 NPs in the inhalation chamber (130.8 μg/m3) was significantly lower. This 11-week study on mice confirmed in vivo the presence of TiO2 NPs in lung macrophages and type II pneumocytes including their intracellular localization by using the electron microscopy and the state-of-the-art methods detecting NPs' chemical identity/crystal structure, such as the energy-dispersed X-ray spectroscopy (EDX), cathodoluminescence (CL), and detailed diffraction pattern analysis using powder nanobeam diffraction (PNBD). For the first time in inhalation study in vivo, the alterations in erythrocyte morphology with evidence of echinocytes and stomatocytes, accompanied by iron accumulation in spleen, liver, and kidney, are reported following NP's exposure. Together with the histopathological evidence of hyperaemia in the spleen and kidney, and haemosiderin presence in the spleen, the finding of NPs containing iron might suggest the increased decomposition of damaged erythrocytes. The detection of TiO2 NPs on erythrocytes through CL analysis confirmed their potential systemic availability. On the contrary, TiO2 NPs were not confirmed in other organs (spleen, liver, and kidney); Ti was detected only in the kidney near the detection limit.

Department of Bionanoscience Delft University of Technology Delft The Netherlands

Department of Environmental Analytical Chemistry Institute of Analytical Chemistry Czech Academy of Sciences Brno Czech Republic

Department of Environmental Engineering Institute of Chemical Process Fundamentals Czech Academy of Sciences Prague Czech Republic

Department of Pathological Morphology and Parasitology Faculty of Veterinary Medicine University of Veterinary Sciences Brno Czech Republic

Department of Pharmacology and Toxicology Veterinary Research Institute Brno Czech Republic

Institute of Scientific Instruments Czech Academy of Sciences Brno Czech Republic

Kavli Institute of Nanoscience Delft University of Technology Delft The Netherlands

Laboratory of Neurobiology and Molecular Psychiatry Department of Biochemistry Faculty of Science Masaryk University Brno Czech Republic

Laboratory of Neurobiology and Pathological Physiology Institute of Animal Physiology and Genetics Czech Academy of Sciences Brno Czech Republic

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