Chemical Process Engineering and Forest Products Research Centre

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Publications

Analysis of the In Vitro Toxicity of Nanocelluloses in Human Lung Cells as Compared to Multi-Walled Carbon Nanotubes

Publication . 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 João

Cellulose 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.

2022-04-22Journal article

Open access

Cyto-genotoxic effects of distinct micro/nanocelluloses in human osteoblastic and mice fibroblastic cells

Publication . Ventura, Célia; Marques, Catarina; Cadete, João; Vilar, Madalena; Pedrosa, J.F.S.; Pinto, P.; Rosa, R.R.; Fernandes, S.N.; Godinho, M.H.; Ferreira, P.J.T.; Louro, Henriqueta; Silva, Maria João

The unique characteristics of micro/nanocelluloses (MNCs) have been boosting their use in a wide variety of industrial and biomedical applications. With the expected decrease of their production cost, it is likely to observe an even faster growing adoption of these materials in the coming years. With the increasing use of MNCs comes an increased likelihood of human exposure to these materials, raising concerns about potential human health effects. The number of studies on the potential adverse effects of MNCs is still scarce and sometimes inconclusive. The aim of the present study is to shed some light on the impact of human exposure to cellulose-based nanomaterials. For that, three MNCs were produced from bleached Eucalyptus kraft pulp using different pretreatments. A microfibrillated (CMF) and a nanofibrillated cellulose (CNF) were respectively obtained by enzymatic and TEMPO-mediated oxidation pretreatments followed by high-pressure homogenization. In addition, cellulose nanocrystals (CNC) were obtained by acid hydrolysis with diluted sulfuric acid. The potential cytotoxicity of the MNCs was evaluated in vitro in two mammalian cell lines (human MG-63 osteoblasts and mice V79 lung fibroblasts) by the MTT and the clonogenic assays, and the genotoxicity was assessed by the micronucleus assay. Cytotoxicity was observed by the clonogenic assay in V79 cells, particularly for CNC, but not by the MTT assay. CNF induced micronuclei in both cell lines and nucleoplasmic bridges in MG-63 cells. CMF and CNC induced micronuclei and nucleoplasmic bridges in MG-63 cells, but not in V79 cells. From the results, it was concluded that under the tested conditions all MNCs present cytotoxicity and genotoxicity, although at different concentration levels, which may be related to their physicochemical differences, to the availability for cell uptake, and to differences in the DNA damage response of the cell model.

2022-06-28Conference object

Restricted access

Assessing the Genotoxicity of Cellulose Nanomaterials in a Co-Culture of Human Lung Epithelial Cells and Monocyte-Derived Macrophages

Publication . 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 João

Cellulose 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.

2023-08-21Journal article

Open access