title: Toxicity of antimony, copper, cobalt, manganese, titanium and zinc oxide nanoparticles for the alveolar and intestinal epithelial barrier cells in vitro.
abstract: Heavy metals are found naturally on Earth and exposure to them in the living environment is increasing as a consequence of human activity. The toxicity of six different metal oxide nanoparticles (NP) at different points in time was compared using resazurin assay. After incubating Caco2 and A549 cells with 100 μg/mL of Sb2O3, Mn3O4and TiO2nanoparticles (NPs) for 24 h no toxic effects were observed while Co3O4and ZnO NPs had moderate effects and CuO NPs were toxic below 100 μg/mL (24 h EC25= 11 for A549 and 71 μg/mL for Caco2). The long-term monitoring (up to 9 days) of cells to NPs revealed that the toxic effects of Mn3O4and Sb2O3NPs remarkably increased over time. The 9 day EC50values for Sb2O3NPs were 22 and 48 μg/mL for A549 and Caco2 cells; and for Mn3O4NPs were 47 and 29 μg/mL for A549 and Caco2 cells, respectively. In general, the sensitivity of the cell lines in the resazurin assay was comparable. Trans epithelial electrical resistance (TEER) measurements were performed for both cell types exposed to Co3O4, Sb2O3and CuO NPs. In TEER assay, the Caco2 cells were more susceptible to the toxic effects of these NPs than A549 cells, where the most toxic NPs were the Sb2O3NPs: the permeability of the Caco2 cell layer exposed to 10 μg/mL Sb2O3NPs already increased after 24 h of exposure.
authors.affiliation: Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia. tiina.titma@tlu.ee.|School of Natural Sciences and Health, Tallinn University, Narva mnt. 25, 10120, Tallinn, Estonia. tiina.titma@tlu.ee.|Laboratory of Bioorganic Chemistry, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia. tiina.titma@tlu.ee.|Technomedicum, Tallinn University of Technology, Ehitajate tee 5, 19086, Tallinn, Estonia. tiina.titma@tlu.ee.
authors.forename: T
authors.identifier: http://orcid.org/0000-0002-4935-8914
authors.initials: T
authors.lastname: Titma
authors.affiliation: School of Natural Sciences and Health, Tallinn University, Narva mnt. 25, 10120, Tallinn, Estonia.
authors.forename: R
authors.initials: R
authors.lastname: Shimmo
authors.affiliation: Laboratory of Bioorganic Chemistry, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia.
authors.forename: J
authors.initials: J
authors.lastname: Siigur
authors.affiliation: Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, 12618, Tallinn, Estonia.
authors.forename: A
authors.initials: A
authors.lastname: Kahru
keywords: A549 cells; Caco2 cells; Long term viability; Metal oxide nanoparticles; Non-monotonic dose–response (NMDR); Transepithelial electrical resistance (TEER)