Insight into the primary mode of action of TiO sub(2) nanoparticles on Escherichia coli in the dark

Large-scale production and incorporation of titanium dioxide nanoparticles (NP-TiO sub(2)) in consumer products leads to their potential release into the environment and raises the question of their toxicity. The bactericidal mechanism of NP-TiO sub(2) under UV light is known to involve oxidative st...

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Bibliographic Details
Published in:Proteomics (Weinheim) 2015-01, Vol.15 (1), p.98-113
Main Authors: Sohm, Benedicte, Immel, Francoise, Bauda, Pascale, Pagnout, Christophe
Format: Article
Language:English
Subjects:
Escherichia coli
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Summary:Large-scale production and incorporation of titanium dioxide nanoparticles (NP-TiO sub(2)) in consumer products leads to their potential release into the environment and raises the question of their toxicity. The bactericidal mechanism of NP-TiO sub(2) under UV light is known to involve oxidative stress due to the generation of reactive oxygen species. In the dark, several studies revealed that NP-TiO sub(2) can exert toxicological effects. However, the mode of action of these nanoparticles is still controversial. In the present study, we used a combination of fluorescent probes to show that NP-TiO sub(2) causes Escherichia coli membrane depolarization and loss of integrity, leading to higher cell permeability. Using both transcriptomic and proteomic global approaches we showed that this phenomenon translates into a cellular response to osmotic stress, metabolism of cell envelope components and uptake/metabolism of endogenous and exogenous compounds. This primary mechanism of bacterial NP-TiO sub(2) toxicity is supported by the observed massive cell leakage of K super(+)/Mg super(2+) concomitant with the entrance of extracellular Na super(+), and by the depletion of intracellular ATP level.
ISSN:1615-9853
1615-9861
DOI:10.1002/pmic.201400101