title: Moving into advanced nanomaterials. Toxicity of rutile TiO2nanoparticles immobilized in nanokaolin nanocomposites on HepG2 cell line.
abstract: Immobilization of nanoparticles on inorganic supports has been recently developed, resulting in the creation of nanocomposites. Concerning titanium dioxide nanoparticles (TiO2NPs1), these have already been developed in conjugation with clays, but so far there are no available toxicological studies on these nanocomposites. The present work intended to evaluate the hepatic toxicity of nanocomposites (C-TiO22), constituted by rutile TiO2NPs immobilized in nanokaolin (NK3) clay, and its individual components. These nanomaterials were analysed by means of FE-SEM4and DLS5analysis for physicochemical characterization. HepG2 cells were exposed to rutile TiO2NPs, NK clay and C-TiO2nanocomposite, in the presence and absence of serum for different exposure periods. Possible interferences with the methodological procedures were determined for MTT,6neutral red uptake, alamar blue (AB), LDH,7and comet assays, for all studied nanomaterials. Results showed that MTT, AB and alkaline comet assay were suitable for toxicity analysis of the present materials after slight modifications to the protocol. Significant decreases in cell viability were observed after exposure to all studied nanomaterials. Furthermore, an increase in HepG2 DNA damage was observed after shorter periods of exposure in the absence of serum proteins and longer periods of exposure in their presence. Although the immobilization of nanoparticles in micron-sized supports could, in theory, decrease the toxicity of single nanoparticles, the selection of a suitable support is essential. The present results suggest that NK clay is not the appropriate substrate to decrease TiO2NPs toxicity. Therefore, for future studies, it is critical to select a more appropriate substrate for the immobilization of TiO2NPs.
authors.affiliation: Department of Environmental Health, Portuguese National Institute of Health, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal. Electronic address: mjbessa8@gmail.com.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Bessa
authors.affiliation: Department of Environmental Health, Portuguese National Institute of Health, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas 135, 4050-600, Porto, Portugal. Electronic address: cstcosta@gmail.com.
authors.forename: Carla
authors.initials: C
authors.lastname: Costa
authors.affiliation: Electroceramic Department, Instituto de Cerámica y Vidrio, CSIC, Campus de Cantoblanco, Calle de Kelson, 5, 28049 Madrid, Spain. Electronic address: jjreinosa@icv.csic.es.
authors.forename: Julian
authors.initials: J
authors.lastname: Reinosa
authors.affiliation: Department of Environmental Health, Portuguese National Institute of Health, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas 135, 4050-600, Porto, Portugal. Electronic address: cristianacostapereira@gmail.com.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Pereira
authors.affiliation: Department of Environmental Health, Portuguese National Institute of Health, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas 135, 4050-600, Porto, Portugal. Electronic address: teixeirafraga@hotmail.com.
authors.forename: Sónia
authors.initials: S
authors.lastname: Fraga
authors.affiliation: Electroceramic Department, Instituto de Cerámica y Vidrio, CSIC, Campus de Cantoblanco, Calle de Kelson, 5, 28049 Madrid, Spain. Electronic address: jfernandez@icv.csic.es.
authors.forename: José
authors.initials: J
authors.lastname: Fernández
authors.affiliation: Catalytic Spectroscopy Laboratory, Instituto de Catálisis y Petroleoquímica, ICP-CSIC, Madrid, Spain. Electronic address: miguel.banares@csic.es.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Bañares
authors.affiliation: Department of Environmental Health, Portuguese National Institute of Health, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas 135, 4050-600, Porto, Portugal. Electronic address: jpft12@gmail.com.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Teixeira
mesh_terms: D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D056945:Hep G2 Cells; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D009152:Mutagenicity Tests / Q000379:methods; D053761:Nanocomposites / Q000737:chemistry / Q000633:toxicity*; D014025:Titanium / Q000737:chemistry / Q000633:toxicity*
chemical_list: C009495:titanium dioxide; D014025:Titanium
keywords: Cytotoxicity; Genotoxicity; In vitro; Interferences studies; Kaolin nanoclay; Titanium dioxide nanoparticles