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Efeitos tóxicos dos nanotubos de carbono em células do trato respiratório humano
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Advisor(s)
Abstract(s)
Os nanotubos de carbono de parede múltipla (NTCs) são nanomateriais
(NM) frequentemente utilizados como compósitos estruturais, em aplicações
energéticas e em eletrónica. Com o objetivo de contribuir para a
avaliação da sua segurança para o homem, foi investigada a toxicidade
de vários NTC (NM-400, NM-401, NM-402 e NM-403) considerando a
relação entre as suas propriedades físico-químicas e toxicológicas. Os
efeitos citotóxicos foram analisados através do ensaio clonogénico e
do índice replicativo, enquanto a genotoxicidade foi avaliada através
dos ensaios do cometa e do micronúcleo, em duas linhas celulares do
trato respiratório humano, as células A549 e Beas-2B. A exposição das
células durante 48h revelou que apenas o NM-401 era citotóxico em
ambos os tipos de células, mas, após uma exposição de 8 dias, todos os
NTCs eram citotóxicos nas células A549. A análise de correlação sugeriu
uma associação entre a dimensão dos NTCs no meio de cultura e a sua
citotoxicidade. O ensaio do cometa não revelou indução de quebras na
molécula de DNA. Contudo, os NM-401 e NM-402 induziram a formação
de micronúcleos em A549, mas não em Beas-2B. Como estes são os
NTCs mais longos, o comprimento parece ser um fator determinante
para a genotoxicidade.
Multi-walled carbon nanotubes (CNTs) are nanomaterials (NMs) frequently used in applications such as structural composites, energy applications and electronics. To contribute to the safety assessment of CNTs, this work investigated the toxicological effects of CNTs (NM-400, NM-401, NM-402 and NM-403), in relation to their physicochemical characteristics. The cytotoxic effects were analysed using the clonogenic assay and replication index, while genotoxic effects were evaluated by the comet and micronucleus assays, in two types of human respiratory cells, A549 and Beas-2B. The 48h-exposure of cells revealed that only NM-401 was cytotoxic in both cell lines, but after 8-days exposure, all the tested CNTs were cytotoxic in A549 cells. Correlation analysis suggested an association between the CNTs’ size in cell medium and cytotoxicity. Using the comet assay, no induction of DNA damage was observed. However, NM-401 and NM-402 induced micronucleus in A549 cells but not in Beas-2B. NM-401 and NM-402 are the two longest MWCNTs analyzed in this work and therefore length of the CNT may be determinant for genotoxicity. The different CNTs effect in the two cell lines is explained in view of the size-distribution of MWCNTs in the cell medium, rather than cell’s specificities.
Multi-walled carbon nanotubes (CNTs) are nanomaterials (NMs) frequently used in applications such as structural composites, energy applications and electronics. To contribute to the safety assessment of CNTs, this work investigated the toxicological effects of CNTs (NM-400, NM-401, NM-402 and NM-403), in relation to their physicochemical characteristics. The cytotoxic effects were analysed using the clonogenic assay and replication index, while genotoxic effects were evaluated by the comet and micronucleus assays, in two types of human respiratory cells, A549 and Beas-2B. The 48h-exposure of cells revealed that only NM-401 was cytotoxic in both cell lines, but after 8-days exposure, all the tested CNTs were cytotoxic in A549 cells. Correlation analysis suggested an association between the CNTs’ size in cell medium and cytotoxicity. Using the comet assay, no induction of DNA damage was observed. However, NM-401 and NM-402 induced micronucleus in A549 cells but not in Beas-2B. NM-401 and NM-402 are the two longest MWCNTs analyzed in this work and therefore length of the CNT may be determinant for genotoxicity. The different CNTs effect in the two cell lines is explained in view of the size-distribution of MWCNTs in the cell medium, rather than cell’s specificities.
Description
Keywords
Nanotubos de Carbono Infecções Respiratórias Genotoxicidade Ambiental Avaliação do Risco Saúde Ambiental e Ocupacional
Pedagogical Context
Citation
Boletim Epidemiológico Observações. 2017;6(Supl 9):56-59
Publisher
Instituto Nacional de Saúde Doutor Ricardo Jorge, IP