Insight into the primary mode of action of TiO2 nanoparticles on Escherichia coli in the dark.

Abstract : Large-scale production and incorporation of titanium dioxide nanoparticles (NP-TiO2 ) in consumer products leads to their potential release into the environment and raises the question of their toxicity. The bactericidal mechanism of NP-TiO2 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-TiO2 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-TiO2 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-TiO2 toxicity is supported by the observed massive cell leakage of K(+) /Mg(2+) concomitant with the entrance of extracellular Na(+) , and by the depletion of intracellular ATP level.
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https://hal.archives-ouvertes.fr/hal-01101796
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Submitted on : Friday, January 9, 2015 - 4:31:16 PM
Last modification on : Friday, April 5, 2019 - 11:36:06 AM

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Bénédicte Sohm, Françoise Immel, Pascale Bauda, Christophe Pagnout. Insight into the primary mode of action of TiO2 nanoparticles on Escherichia coli in the dark.. Proteomics, Wiley-VCH Verlag, 2015, 15 (1), pp.98-113. ⟨10.1002/pmic.201400101⟩. ⟨hal-01101796⟩

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