Till Jasper Meyer a, Nursen Tekin a, Peter Hense b, Totta Ehret-Kasemo a, Nina Lodes c, Manuel Stöth a, Pascal Ickrath a, Thomas Gehrke a, Rudolf Hagen a, Sofia Dembski c d, Michael Peer e, Maria R. Steinke c d, Agmal Scherzad a, Stephan Hackenberg f
a University Hospital Würzburg, Department of Oto-Rhino-Laryngology, Plastic, Aesthetic & Reconstructive Head and Neck Surgery, Josef-Schneider-Straße 11, 97080 Würzburg, Germany
b Bochum University of Applied Sciences, Department Civil and Environmental Engineering, Am Hochschulcampus 1, 44801 Bochum, Germany
c University Hospital Würzburg, Chair of Tissue Engineering and Regenerative Medicine, Röntgenring 11, 97070 Würzburg, Germany
d Fraunhofer Institute for Silicate Research ISC, Neunerplatz 2, 97082 Würzburg, Germany
e Fraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT, Institute Branch Sulzbach-Rosenberg, An der Maxhütte 1, 92237 Sulzbach-Rosenberg, Germany
f RWTH Aachen University Hospital, Department of Otorhinolaryngology – Head and Neck Surgery, Pauwelsstraße 30, 52074 Aachen, Germany
Printer toner particles (TPs) are a common, potentially hazardous substance, with an unclear toxicological impact on the respiratory mucosa. Most of the airways surface is covered by a ciliated respiratory mucosa, therefore appropriate tissue models of the respiratory epithelium with a high in vivo correlation are necessary for in vitro evaluation of airborne pollutants toxicology and the impact on the functional integrity. The aim of this study is the evaluation of TPs toxicology in a human primary cell-based air-liquid-interface (ALI) model of respiratory mucosa. The TPs were analyzed and characterized by scanning electron microscopy, pyrolysis and X-ray fluorescence spectrometry. ALI models of 10 patients were created using the epithelial cells and fibroblasts derived from nasal mucosa samples. TPs were applied to the ALI models via a modified Vitrocell® cloud and submerged in the dosing 0.89 – 892.96 µg/ cm2. Particle exposure and intracellular distribution were evaluated by electron microscopy. The MTT assay and the comet assay were used to investigate cytotoxicity and genotoxicity, respectively. The used TPs showed an average particle size of 3 – 8 µm. Mainly carbon, hydrogen, silicon, nitrogen, tin, benzene and benzene derivates were detected as chemical ingredients. By histomorphology and electron microscopy we observed the development of a highly functional, pseudostratified epithelium with a continuous layer of cilia. Using electron microscopy, TPs could be detected on the cilia surface and also intracellularly. Cytotoxicity was detected from 9 µg/ cm2 and higher, but no genotoxicity after ALI and submerged exposure. The ALI with primary nasal cells represents a highly functional model of the respiratory epithelium in terms of histomorphology and mucociliary differentiation. The toxicological results indicate a weak TP-concentration-dependent cytotoxicity.