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

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.The work was funded by the Portuguese Foundation for Science and Technology (FCT/MCTES), through national funds (PIDDAC) under the project ToxApp4NanoCELFI (PTDC/SAU-PUB/32587/2017). The authors also acknowledge the support of FCT/MCTES to the following projects: LA/P/0037/2020, UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication-i3N, CIEPQPF (UIDB/00102/2020) and ToxOmics, NMS-UNL (UIDP/00009/2020; UIDB/00009/2020). Thanks also to European Cooperation in Science & Technology (COST) Action: CA21159—Understanding interaction light—biological surfaces: possibility for new electronic materials and devices (PhoBioS); Inpactus Project—innovative products and technologies from eucalyptus (Project No. 21874 funded by Portugal 2020 through ERDF in the frame of COMPETE 2020 No. 246/AXIS II/2017)