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DGH - Dissertações de mestrado

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Browsing DGH - Dissertações de mestrado by Subject "A549 cells"

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  • Cyto- and Genotoxicity Assessment of Manufactured Nanomaterials in the A549 Cell Line
    Publication . Saruga, Andreia; Silva, Maria João; Louro, Maria Henriqueta
    A number of nanomaterials (NMs) have been applied in different fields due to their unique physico-chemical properties. As the use and applications have increased in some industries, serious concerns about their potential impact on the environment and the human health have been raised and have been a challenge for the regulatory authorities. This work aimed at assessing the toxicity of three classes of NMs, namely cerium dioxide, CeO2 (NM-212), titanium dioxide, TiO2 (NM-101 and NM-100) and barium sulphate, BaSO4 (NM-220) since they already have a broad range of applications in industry and consumer products. A standardized protocol for NMs dispersion was followed and the quality of the dispersion in the culture medium was evaluated by the dynamic light scattering technique. Different concentrations (0, 1, 3, 10, 30, 75 and 100 μg/cm2) of each nanomaterial were used to expose A549 cells (human lung carcinoma cells) for cytotoxic evaluation through the MTT and clonogenic assays and genotoxicity assessment through the comet and the cytokinesis-blocked micronucleus (CBMN) assays. The results showed a decrease in cell proliferation after exposure to cerium dioxide nanomaterials for 8 days, at the highest concentrations tested and a slight increase in the level of DNA breaks. Concerning the TiO2 NMs, a statistically significant increase in the level of DNA breaks was found for both NMs; however the CBMN assay did not show any increase in the frequency of chromosomal breaks. BaSO4 was the NM that showed the lowest toxicity in cyto- and genotoxicity assays.Even though the present results contribute to assess the hazard of the tested NMs, the real effects of nanomaterials’ exposure to human health are still unclear and an unequivocal conclusion is difficult to present, given the inconsistent and often conflicting results found in the literature. Thus, the application of some nanomaterials in consumer products should be carefully evaluated until definite conclusions about their safety are available.
    2016-09Master thesis Open access Show more