Browsing by Author "Tavares, Daniela S."
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- Co-exposure with CeO2NPs results in an antagonistic effect on the cytotoxicity and genotoxicity of TiO2NP on A549 cellsPublication . Rosário, Fernanda; Vilaça, Cláudia; Costa, Carla; Lopes, Cláudia B.; Estrada, Ana C.; Tavares, Daniela S.; Teixeira, João Paulo; Reis, Ana TeresaObjective: Assess the CYTOTOXIC and GENOTOXIC POTENTIAL resulting from titanium dioxide nanoparticles (TiO2NP) and cerium oxide nanoparticles (CeO2NP) co-exposure in human lung epithelial cell line A549.
- Cytotoxic effects of single and binary mixtures of metal oxide nanoparticles and metal(loid) on A549 human cell line.Publication . Rosário, Fernanda; Bessa, Maria João; Brandão, Fátima; Costa, Carla; Lopes, Cláudia B.; Estrada, Ana Cristina; Tavares, Daniela S.; Teixeira, João Paulo; Reis, Ana TeresaBackground, Motivation and Objective: The need to assess the toxicity resulting from exposure to mixtures of chemicals has been recognized by the WHO and EU, as humans are simultaneously exposed to an array of natural and anthropogenic contaminants. Of particular interest are the potential combined effects resulting from interaction of nanoparticles (NPs) and metals. While the first are the current driving force for emerging contaminants, the latter, as legacy contaminants, remain a concern. Metals show strong affinity to NPs, which can change the uptake and toxicity to the organism of each individual contaminant. Studying the effects on the respiratory tract is of upmost relevance because of its constant contact with xenobiotics, resulting in adverse effects on the lung. Considering the above, the objective of this work was to assess and compare viability, cell cycle, and uptake of A549 cells after exposure to single and binary mixtures of titanium dioxide nanoparticles (TiO2NP), cerium oxide nanoparticles (CeO2NP), arsenic (As) and mercury (Hg). These chemicals were chosen because: 1) TiO2NP are among the most abundantly used NPs; 2) CeO2NP have been used in nanomedicine for its high biocompatibility and cytoprotective effect; and 3) As and Hg due to their non‐biodegradable, persistent, and extremely toxic character. This work intends to support adequate human risk assessment resulting from co-exposure to multiple contaminants.
- In Vitro Hepatotoxic and Neurotoxic Effects of Titanium and Cerium Dioxide Nanoparticles, Arsenic and Mercury Co-ExposurePublication . Rosário, Fernanda; Costa, Carla; Lopes, Cláudia B.; Estrada, Ana C.; Tavares, Daniela S.; Pereira, Eduarda; Teixeira, João Paulo; Reis, Ana TeresaConsidering the increasing emergence of new contaminants, such as nanomaterials, mixing with legacy contaminants, including metal(loid)s, it becomes imperative to understand the toxic profile resulting from these interactions. This work aimed at assessing and comparing the individual and combined hepatotoxic and neurotoxic potential of titanium dioxide nanoparticles (TiO2NPs 0.75-75 mg/L), cerium oxide nanoparticles (CeO2NPs 0.075-10 μg/L), arsenic (As 0.01-2.5 mg/L), and mercury (Hg 0.5-100 mg/L) on human hepatoma (HepG2) and neuroblastoma (SH-SY5Y) cells. Viability was assessed through WST-1 (24 h) and clonogenic (7 days) assays and it was affected in a dose-, time- and cell-dependent manner. Higher concentrations caused greater toxicity, while prolonged exposure caused inhibition of cell proliferation, even at low concentrations, for both cell lines. Cell cycle progression, explored by flow cytometry 24 h post-exposure, revealed that TiO2NPs, As and Hg but not CeO2NPs, changed the profiles of SH-SY5Y and HepG2 cells in a dose-dependent manner, and that the cell cycle was, overall, more affected by exposure to mixtures. Exposure to binary mixtures revealed either potentiation or antagonistic effects depending on the composition, cell type and time of exposure. These findings prove that joint toxicity of contaminants cannot be disregarded and must be further explored.
- Unravelling the Potential Cytotoxic Effects of Metal Oxide Nanoparticles and Metal(Loid) Mixtures on A549 Human Cell LinePublication . Rosário, Fernanda; Bessa, Maria João; Brandão, Fátima; Costa, Carla; Lopes, Cláudia B.; Estrada, Ana C.; Tavares, Daniela S.; Teixeira, João Paulo; Reis, Ana TeresaHumans are typically exposed to environmental contaminants' mixtures that result in different toxicity than exposure to the individual counterparts. Yet, the toxicology of chemical mixtures has been overlooked. This work aims at assessing and comparing viability and cell cycle of A549 cells after exposure to single and binary mixtures of: titanium dioxide nanoparticles (TiO2NP) 0.75-75 mg/L; cerium oxide nanoparticles (CeO2NP) 0.0.75-10 μg/L; arsenic (As) 0.75-2.5 mg/L; and mercury (Hg) 5-100 mg/L. Viability was assessed through water-soluble tetrazolium (WST-1) and thiazolyl blue tetrazolium bromide (MTT) (24 h exposure) and clonogenic (seven-day exposure) assays. Cell cycle alterations were explored by flow cytometry. Viability was affected in a dose- and time-dependent manner. Prolonged exposure caused inhibition of cell proliferation even at low concentrations. Cell-cycle progression was affected by TiO2NP 75 mg/L, and As 0.75 and 2.5 μg/L, increasing the cell proportion at G0/G1 phase. Combined exposure of TiO2NP or CeO2NP mitigated As adverse effects, increasing the cell surviving factor, but cell cycle alterations were still observed. Only CeO2NP co-exposure reduced Hg toxicity, translated in a decrease of cells in Sub-G1. Toxicity was diminished for both NPs co-exposure compared to its toxicity alone, but a marked toxicity for the highest concentrations was observed for longer exposures. These findings prove that joint toxicity of contaminants must not be disregarded.