title: Interaction of single-walled carbon nanotubes and saxitoxin: Ab initio simulations and biological responses in hippocampal cell line HT-22.
abstract: Saxitoxins (STXs) are potent neurotoxins that also induce cytotoxicity through the generation of reactive oxygen species. Carbon nanotubes (CNTs) are nanomaterials that can promote a Trojan horse effect, facilitating the entry of toxic molecules to cells when adsorbed to nanomaterials. The interaction of pristine single-walled (SW)CNTs and carboxylated (SWCNT-COOH) nanotubes with STX was evaluated by ab initio simulation and bioassays using the cell line HT-22. Cells (5 × 104cells/mL) were exposed to SWCNT and SWCNT-COOH (5 μg mL-1), STX (200 μg L-1), SWCNT+STX, and SWCNT-COOH+STX for 30 min or 24 h. Results of ab initio simulation showed that the interaction between SWCNT and SWCNT-COOH with STX occurs in a physisorption. The interaction of SWCNT+STX induced a decrease in cell viability. Cell proliferation was not affected in any treatment after 30 min or 24 h of exposure (p > 0.05). Treatment with SWCNT-COOH induced high reactive oxygen species levels, an effect attenuated in SWCNT-COOH+STX treatment. In terms of cellular oxygen consumption, both CNTs when coexposed with STX antagonize the toxin effect. Based on these results, it can be concluded that the results obtained in vitro corroborate the semiempirical evidence found using density functional theory ab initio simulation. Environ Toxicol Chem 2017;36:1728-1737. © 2016 SETAC.
authors.affiliation: Institute of Biological Science, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.|Postgraduate Program in Physiological Sciences, Comparative Animal Physiology, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Patrícia
authors.initials: P
authors.lastname: Ramos
authors.affiliation: Institute of Biological Science, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Marcos
authors.initials: M
authors.lastname: Schmitz
authors.affiliation: Institute of Biological Science, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Daza
authors.initials: D
authors.lastname: Filgueira
authors.affiliation: Institute of Biological Science, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.|Postgraduate Program in Physiological Sciences, Comparative Animal Physiology, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Votto
authors.affiliation: Institute of Biological Science, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.|Postgraduate Program in Physiological Sciences, Comparative Animal Physiology, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Michael
authors.initials: M
authors.lastname: Durruthy
authors.affiliation: Postgraduate Program in , Technological and Environmental Chemistry, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Marcos
authors.initials: M
authors.lastname: Gelesky
authors.affiliation: Postgraduate Program in , Technological and Environmental Chemistry, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: Caroline
authors.initials: C
authors.lastname: Ruas
authors.affiliation: Cyanobacteria and Ficotoxin Laboratory, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: João
authors.initials: J
authors.lastname: Yunes
authors.affiliation: Franciscan University Center (UNIFRA), Santa Maria, Rio Grande do Sul, Brazil.|Postgraduate Program in Nanoscience, Franciscan University Center (UNIFRA), Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Mariana
authors.initials: M
authors.lastname: Tonel
authors.affiliation: Franciscan University Center (UNIFRA), Santa Maria, Rio Grande do Sul, Brazil.|Postgraduate Program in Nanoscience, Franciscan University Center (UNIFRA), Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Solange
authors.initials: S
authors.lastname: Fagan
authors.affiliation: Institute of Biological Science, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.|Postgraduate Program in Physiological Sciences, Comparative Animal Physiology, Federal University of Rio Grande (FURG), Rio Grande, Rio Grande do Sul, Brazil.
authors.forename: José
authors.initials: J
authors.lastname: Monserrat
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012530:Saxitoxin / Q000737:chemistry / Q000633:toxicity*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002264:Carboxylic Acids; D037742:Nanotubes, Carbon; D017382:Reactive Oxygen Species; D012530:Saxitoxin
keywords: Carbon nanotubes; Cell viability; Density functional theory; HT-22 cell; Saxitoxin