Browsing by Author "Fernandes, Susete N."
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- Analysis of the In Vitro Toxicity of Nanocelluloses in Human Lung Cells as Compared to Multi-Walled Carbon NanotubesPublication . Pinto, Fátima; Lourenço, Ana Filipa; Pedrosa, Jorge F.S.; Gonçalves, Lídia; Ventura, Célia; Vital, Nádia; Bettencourt, Ana; Fernandes, Susete N.; da Rosa, Rafaela R.; Godinho, Maria Helena; Louro, Henriqueta; Ferreira, Paulo J.T.; Silva, Maria JoãoCellulose micro/nanomaterials (CMNM), comprising cellulose microfibrils (CMF), nanofibrils (CNF), and nanocrystals (CNC), are being recognized as promising bio-nanomaterials due to their natural and renewable source, attractive properties, and potential for applications with industrial and economical value. Thus, it is crucial to investigate their potential toxicity before starting their production at a larger scale. The present study aimed at evaluating the cell internalization and in vitro cytotoxicity and genotoxicity of CMNM as compared to two multi-walled carbon nanotubes (MWCNT), NM-401 and NM-402, in A549 cells. The exposure to all studied NM, with the exception of CNC, resulted in evident cellular uptake, as analyzed by transmission electron microscopy. However, none of the CMNM induced cytotoxic effects, in contrast to the cytotoxicity observed for the MWCNT. Furthermore, no genotoxicity was observed for CNF, CNC, and NM-402 (cytokinesis-block micronucleus assay), while CMF and NM-401 were able to significantly raise micronucleus frequency. Only NM-402 was able to induce ROS formation, although it did not induce micronuclei. Thus, it is unlikely that the observed CMF and NM-401 genotoxicity is mediated by oxidative DNA damage. More studies targeting other genotoxicity endpoints and cellular and molecular events are underway to allow for a more comprehensive safety assessment of these nanocelluloses.
- Assessing the Genotoxicity of Cellulose Nanomaterials in a Co-Culture of Human Lung Epithelial Cells and Monocyte-Derived MacrophagesPublication . Ventura, Célia; Pinto, Fátima; Lourenço, Ana Filipa; Pedrosa, Jorge F. S.; Fernandes, Susete N.; da Rosa, Rafaela R.; Godinho, Maria Helena; Ferreira, Paulo J. T.; Louro, Henriqueta; Silva, Maria JoãoCellulose micro/nanomaterials (CMNMs) are innovative materials with a wide spectrum of industrial and biomedical applications. Although cellulose has been recognized as a safe material, the unique properties of its nanosized forms have raised concerns about their safety for human health. Genotoxicity is an endpoint that must be assessed to ensure that no carcinogenic risks are associated with exposure to nanomaterials. In this study, we evaluated the genotoxicity of two types of cellulose micro/nanofibrils (CMF and CNF) and one sample of cellulose nanocrystals (CNC), obtained from industrial bleached Eucalyptus globulus kraft pulp. For that, we exposed co-cultures of human alveolar epithelial A549 cells and THP-1 monocyte-derived macrophages to a concentration range of each CMNM and used the micronucleus (MN) and comet assays. Our results showed that only the lowest concentrations of the CMF sample were able to induce DNA strand breaks (FPG-comet assay). However, none of the three CMNMs produced significant chromosomal alterations (MN assay). These findings, together with results from previous in vitro studies using monocultures of A549 cells, indicate that the tested CNF and CNC are not genotoxic under the conditions tested, while the CMF display a low genotoxic potential.
- Investigation of potential respiratory adverse effects of micro/nanofibrillated cellulose and cellulose nanocrystals using human lung cell lines.Publication . Pinto, Fátima; Ventura, Célia; Cadete, João; Lourenço, Ana Filipa; Pedrosa, Jorge F.S.; Vital, Nádia; Pereira, Joana F.S.; Matos, Paulo; Gonçalves, Lídia; Bettencourt, Ana; Silva, Catarina C.; Fernandes, Susete N.; Godinho, Maria Helena; Vieira, Luís; Jordan, Peter; Ferreira, Paulo J.T.; Louro, Henriqueta; Silva, Maria JoãoMicro/nanofibrillated (CMF/CNF) and nanocrystalline (CNC) celluloses are innovative materials with enormous potential for industrial and biomedical applications. Their expanding production/application urges the investigation of their safety for human health. This study aimed at investigating the potential respiratory outcomes of two CMF/CNF and one CNC produced from bleached Eucalyptus globulus kraft pulp using human alveolar epithelial (A549) cells grown in monoculture or co-cultured with THP-1 monocyte-derived macrophages, by assessing their cellular uptake, cytotoxic, immunotoxic, genotoxic, and epigenetic effects. The nanocelluloses were characterized for their physicochemical properties: CMF displays a low percentage of nanofibrils while CNF comprises 100% fibrils with a diameter (D) circa 11 nm; CNC consists of nanorods with D of 4-5 nm and aspect ratio around 42. TEM analysis evidenced that CMF and CNF were internalised into A549 cells whereas CNC were not. Neither cytotoxicity (colorimetric and clonogenic assays) nor ROS induction was observed for any of the nanocelluloses. CMF caused chromosomal alterations (in vitro micronucleus assay) in A549 cells while negative results were obtained in co-culture and for the other micro/nanocelluloses in mono- or co-culture. Results in progress of DNA damage and gene mutation analyses will complement mutagenesis assessment. Additionally, potential inflammatory and epigenetic effects are being evaluated. These results contribute to the weight of evidence of nanocelluloses biological effects and knowledge of the underlying molecular mechanisms. Such information will drive the synthesis of the safest nanocelluloses,thus minimising potential negative impacts of their use on human and environmental health.
- Toxicidade da nanocelulose em modelos in vitro: um contributo para a avaliação da sua segurança para a saúde humanaPublication . Ventura, Célia; Pinto, Fátima; Marques, Catarina; Cadete, João; Vilar, Madalena; Lourenço, Ana Filipa; Pedrosa, Jorge F. S.; Fernandes, Susete N.; da Rosa, Rafaela R.; Godinho, Maria Helena; Ferreira, Paulo J.T.; Louro, Henriqueta; Silva, Maria JoãoAs nanoceluloses são nanomateriais inovadores com potencial para uma vasta gama de aplicações industriais e biomédicas. No entanto, a expansão da sua produção tem vindo a suscitar preocupações quanto aos possíveis efeitos, a longo prazo, na saúde humana. Este estudo teve como objetivo avaliar a segurança de algumas nanoceluloses produzidas a partir de matéria-prima nacional, através da caracterização da sua potencial toxicidade em células de mamífero. Para tal, testaram-se duas celuloses nano /microfibrilares (CNF e CMF ) e uma celulose nanocristalina (CNC). Analisou-se a citotoxicidade usando ensaios colorimétricos e o ensaio clonogénico, e a genotoxicidade pelo ensaio do micronúcleo in vitro em células pulmonares de mamífero (A549 e V79 ) e em osteoblastos humanos ( MG-63 ). A indução de espécies reativas de oxigénio (ROS) e a internalização celular foram também estudadas nas células A549. Observou- -se citotoxicidade no ensaio clonogénico, principalmente no caso da CNC, mas não nos restantes ensaios, não havendo também indução de ROS. Todas as nanoceluloses revelaram efeitos genotóxicos nalgumas concentrações, uma vez que induziram micronúcleos e /ou pontes nucleoplásmicas num dos modelos celulares. Para além disso, visualizou-se a internalização da CNF e CMF, mas não da CNC, em células A549. Esta primeira avaliação toxicológica veio contribuir para prevenir a exposição a materiais celulósicos potencialmente perigosos, procurando impulsionar o desenvolvimento de materiais inovadores e mais seguros.