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Issue 116, 2016
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Pro-oxidant effects of nano-TiO2 on Chlamydomonas reinhardtii during short-term exposure

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Abstract

This study sheds light on the short-term dynamics of pro-oxidant processes related to the exposure of C. reinhardtii microalgae to nano-TiO2 using (a) conventional fluorescence probes for cellular pro-oxidant process and (b) a recently developed cytochrome c biosensor for the continuous quantification of extracellular H2O2. The main aims are to investigate nano-TiO2 toxicity and the modifying factors thereof based on the paradigm of oxidative stress and to explore the utility of extracellular H2O2 as a potential biomarker of the observed cellular responses. This is the first study to provide continuous quantitative data on abiotic and biotic nano-TiO2-driven H2O2 generation to systematically investigate the link between extracellular and cellular pro-oxidant responses. Acute exposures of 1 h were performed in two different exposure media (MOPS and lake water), with nominal particle concentrations from 10 mg L−1 to 200 mg L−1, with and without UV pre-illumination. Abiotic and biotic extracellular H2O2 were continuously measured with the biosensor and complemented with endpoints for abiotic ROS (H2DCF-DA), oxidative stress (CellROX® Green) and damage (propidium iodide) measured by flow cytometry at the beginning and end of exposure. Results showed that nano-TiO2 suspensions generated ROS under UV light (abiotic origin) and promoted ROS accumulation in C. reinhardtii (biotic origin). However, extracellular and intracellular pro-oxidant processes differed. Hence, extracellular H2O2 cannot per se serve as a predictor of cellular oxidative stress or damage. The main predictors best describing the cellular responses included “exposure medium”, “exposure time”, “UV treatment” as well as “exposure concentration”.

Graphical abstract: Pro-oxidant effects of nano-TiO2 on Chlamydomonas reinhardtii during short-term exposure

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Publication details

The article was received on 28 Jun 2016, accepted on 01 Dec 2016 and first published on 05 Dec 2016


Article type: Paper
DOI: 10.1039/C6RA16639C
Citation: RSC Adv., 2016,6, 115271-115283
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    Pro-oxidant effects of nano-TiO2 on Chlamydomonas reinhardtii during short-term exposure

    N. von Moos, V. B. Koman, C. Santschi, O. J. F. Martin, L. Maurizi, A. Jayaprakash, P. Bowen and V. I. Slaveykova, RSC Adv., 2016, 6, 115271
    DOI: 10.1039/C6RA16639C

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