Cytotoxicity of TiO2 nanoparticles towards freshwater sediment microorganisms at low exposure concentrations

Kumari, Jyoti and Kumar, Deepak and Mathur, Ankita and Naseer, Arif and Kumar, Ravi Ranjan and Chandrasekaran, Prathna Thanjavur and Chaudhuri, Gouri and Pulimi, Mrudula and Raichur, Ashok M and Babu, S and Chandrasekaran, Natarajan and Nagarajan, R and Mukherjee, Amitava (2014) Cytotoxicity of TiO2 nanoparticles towards freshwater sediment microorganisms at low exposure concentrations. In: ENVIRONMENTAL RESEARCH, 135 . pp. 333-345.

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Abstract

There is a persistent need to assess the effects of TiO2 nanoparticles on the aquatic ecosystem owing to their increasing usage in consumer products and risk of environmental release. The current study is focused on TiO2 nanoparticle-induced acute toxicity at sub-ppm level (<= 1 ppm) on the three different freshwater sediment bacterial isolates and their consortium under two different irradiation (visible light and dark) conditions. The consortium of the bacterial isolates was found to be less affected by the exposure to the nanoparticles compared to the individual cells. The oxidative stress contributed considerably towards the cytotoxicity under both light and dark conditions. A statistically significant increase in membrane permeability was noted under the dark conditions as compared to the light conditions. The optical and fluorescence microscopic images showed aggregation and chain formation of the bacterial cells, when exposed to the nanoparticles. The electron microscopic (SEM, TEM) observations suggested considerable damage of cells and bio-uptake of nanoparticles. The exopolysaccrides (EPS) production and biofilm formation were noted to increase in the presence of the nanoparticles, and expression of the key genes involved in biofilm formation was studied by RT-PCR. (C) 2014 Elsevier Inc. All rights reserved.

Item Type:	Journal Article
Publication:	ENVIRONMENTAL RESEARCH
Publisher:	ACADEMIC PRESS INC ELSEVIER SCIENCE
Additional Information:	Copy right for this article belongs to the ACADEMIC PRESS INC ELSEVIER SCIENCE, 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA
Keywords:	TiO2 NPs; Bacteria; Visible light and dark conditions; Consortium
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	06 Feb 2015 14:56
Last Modified:	06 Feb 2015 14:56
URI:	http://eprints.iisc.ac.in/id/eprint/50784

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