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- Quaternary mixtures of TiO2NP, CeO2NP, arsenic, and mercury potentiate A549, HepG2 and SH-SY5Y cells cytotoxicityPublication . Rosário, Fernanda; Costa, Carla; Teixeira, João; Reis, Ana TeresaIntroduction: Nanoparticles (NP) released to the environment interact with pre-existing contaminants, potentially leading to cytotoxicity and raising concerns regarding human safety to co- exposure to multiple chemicals. This work assesses and compares viability of A549, HepG2 and SH-SY5Y cells after short (24h; WST-1 assay) and long-term (7 days; clonogenic assay) exposure to single and quaternary mixtures of: titanium dioxide nanoparticles (TiO2NP) 0.75; 75 mg/L; cerium oxide nanoparticles (CeO2NP) 0.1; 10 μg/L; arsenic (As) 0.01; 0.75; 2.5 mg/L; and mercury (Hg) 0.5; 10; 20 mg/L. Mixtures were divided in four groups: low, mid-low, mid- high and high.
- Biocompatibility evaluation of CeO2 nanoparticles to be employed as nanodrugs in brain cancer nanomedicinePublication . Fernández-Bertólez, Natália; Touzani, Assia; Martínez, L.; Reis, Ana Teresa; Fraga, Sónia; Teixeira, João Paulo; Costa, Carla; Pásaro, Eduardo; Laffon, Blanca; Valdiglesias, VanessaCerium dioxide nanoparticles (CeO2NP) have recently gained attention for their unique structure-dependent properties, antioxidant enzyme-like behaviour, ROS scavenging activity and great potential for biomedical applications. In addition to their antioxidant and anti-inflammatory activity, CeO2NP are also known to exhibit anticancer potential, providing an attractive opportunity for use in cancer therapy, as a pharmacological agent and/or in drug/gene delivery systems [1]. Therefore, the main objective of this STSM was to evaluate the cytotoxic and genotoxic effects on human glioblastoma A172 cells exposed for 3, 24 and 48h to CeO2NP (1- 100µg/ml), to verify their safety to be used as possible nanomedicines for brain cancer treatment, specifically glioblastoma [2]. In addition, cell-specific differences in nanoceria effect were evaluated by comparing the results obtained with those observed in human neuronal SH-SY5Y cells exposed under the same experimental conditions. After carrying out the physicochemical characterization and analysing the cellular uptake of the CeO2NP, potential alterations in cell viability (MTT assay) and induction of DNA double-strand breaks (γH2AX assay) caused by the exposure were determined. The possible NP interference with assay methodologies was previously addressed and eliminated when necessary. Results obtained showed that, although there was a significant dose- and time-dependent internalization of NP by both cell types, nanoceria induced scarce cytotoxicity or genotoxicity in both cell lines, being restricted to the highest doses and longer exposure time tested. In general, data obtained suggest a high biocompatibility of CeO2NP under the tested conditions, except for glioblastoma cells exposed for 48h from 25 to 100µg/ml. These results provide a better understanding of the CeO2NP interaction with nervous system cells and their possible adverse effects. However, further studies are necessary to delve into the differential behaviour of these NP depending on the nervous cell type tested.
- Integrated Use of Bioaccumulation, Genotoxic, and Haematological Endpoints to Assess the Effect of Water Remediation Strategies on Fish Health: A Complementary StudyPublication . Mieiro, Cláudia; Coelho, João; Reis, Ana Teresa; Castro, Diana; Figueira, Paula; Martinho, Filipe; Pardal, Miguel; Pereira, Eduarda; Pacheco, Mário; Lopes, CláudiaBiosorption successfully remediates saline water contaminated with legacy contaminants, but its effects on the health of marine organisms remain unclear. Therefore, our aim was to address this knowledge gap with data on the accumulation ability, as well as the cytogenetic and biochemical effects in turbot (Scophthalmus maximus). To this end, we exposed turbot for seven days to a mixture of remediated metals (Rem treatments: Cd, Hg, and Pb), with and without the presence of nanoparticles (NP), and compared them with the maximum allowable concentrations (MAC treatment) for effluent discharges. We determined the metal accumulation in the blood and kidney and evaluated haematological changes (red blood cell count, haemoglobin, and mean cell haemoglobin (MCH)) and genotoxicity (erythrocytic nuclear abnormalities assay) in the blood. The results showed that remediation with non-living macroalgae significantly reduced the metallic blood and kidney burdens in the Rem treatments. Furthermore, no genotoxic potential occurred in the Rem and MAC treatments in parallel with the reduction in MCH levels in the Rem treatments, which would reflect hematopoietic disturbances in the MAC. Our results validate biosorption remediation as we achieved a considerable reduction in metal loads while maintaining the health status of fish, highlighting the importance of testing water remediation methods in the biota.
- Effects of Zinc Oxide Nanoparticle Exposure on Human Glial Cells and Zebrafish EmbryosPublication . Valdiglesias, Vanessa; Alba-González, Anabel; Fernández-Bertólez, Natalia; Touzani, Assia; Ramos-Pan, Lucía; Reis, Ana Teresa; Moreda-Piñeiro, Jorge; Yáñez, Julián; Laffon, Blanca; Folgueira, MónicaZinc oxide nanoparticles (ZnO NPs) are among the most widely used nanomaterials. They have multiple applications in cosmetics, textiles, paints, electronics and, recently, also in biomedicine. This extensive use of ZnO NPs notably increases the probability that both humans and wildlife are subjected to undesirable effects. Despite being among the most studied NPs from a toxicological point of view, much remains unknown about their ecotoxicological effects or how they may affect specific cell types, such as cells of the central nervous system. The main objective of this work was to investigate the effects of ZnO NPs on human glial cells and zebrafish embryo development and to explore the role of the released Zn2+ ions in these effects. The effects on cell viability on human A172 glial cells were assessed with an MTT assay and morphological analysis. The potential acute and developmental toxicity was assessed employing zebrafish (Danio rerio) embryos. To determine the role of Zn2+ ions in the in vitro and in vivo observed effects, we measured their release from ZnO NPs with flame atomic absorption spectrometry. Then, cells and zebrafish embryos were treated with a water-soluble salt (zinc sulfate) at concentrations that equal the number of Zn2+ ions released by the tested concentrations of ZnO NPs. Exposure to ZnO NPs induced morphological alterations and a significant decrease in cell viability depending on the concentration and duration of treatment, even after removing the overestimation due to NP interference. Although there were no signs of acute toxicity in zebrafish embryos, a decrease in hatching was detected after exposure to the highest ZnO NP concentrations tested. The ability of ZnO NPs to release Zn2+ ions into the medium in a concentration-dependent manner was confirmed. Zn2+ ions did not seem entirely responsible for the effects observed in the glial cells, but they were likely responsible for the decrease in zebrafish hatching rate. The results obtained in this work contribute to the knowledge of the toxicological potential of ZnO NPs.
- 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.