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Cytotoxicity of aluminium oxide nanoparticles towards fresh water algal isolate at low exposure concentrations

Pakrashi, Sunandan and Dalai, Swayamprava and Prathna, TC and Trivedi, Shruti and Myneni, Radhika and Raichur, Ashok M and Chandrasekaran, N and Mukherjee, Amitava (2013) Cytotoxicity of aluminium oxide nanoparticles towards fresh water algal isolate at low exposure concentrations. In: Aquatic Toxicology, 132 . pp. 34-45.

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Official URL: http://dx.doi.org/10.1016/j.aquatox.2013.01.018

Abstract

The growing commercial applications had brought aluminium oxide nanoparticles under,toxicologists' purview. In the present study, the cytotoxicity of two different sized aluminium oxide nanoparticles (ANP(1), mean hydrodynamic diameter 82.6 +/- 22 nm and ANP(2), mean hydrodynamic diameter 246.9 +/- 39 nm) towards freshwater algal isolate Chlorella ellipsoids at low exposure levels (<= 1 mu g/mL) using sterile lake water as the test medium was assessed. The dissolution of alumina nanoparticles and consequent contribution towards toxicity remained largely unexplored owing to its presumed insoluble nature. Herein, the leached Al3+ ion mediated toxicity has been studied along with direct particulate toxicity to bring out the dynamics of toxicity through colloidal stability, biochemical, spectroscopic and microscopic analyses. The mean hydrodynamic diameter increased with time both for ANP(1) 82.6 +/- 22 nm (0 h) to 246.3 +/- 59 nm (24h), to 1204 +/- 140 nm (72 h)] and ANP(2) 246.9 +/- 39 nm (Oh) to 368.28 +/- 48 nm (24 h), to 1225.96 +/- 186 nm (72 h)] signifying decreased relative abundance of submicron sized particles (<1000 nm). The detailed cytotoxicity assays showed a significant reduction in the viability dependent on dose and exposure. A significant increase in ROS and LDH levels were noted for both ANPs at 1 mu g/mL concentration. The zeta potential and FT-IR analyses suggested surface chemical interaction between nanoparticles and algal cells. The substantial morphological changes and cell wall damage were confirmed through microscopic analyses (SEM, TEM, and CLSM). At 72 h, significant Al3+ ion release in the test medium 0.092 mu g/mL for ANP(1), and 0.19 mu g/mL for ANP(2)] was noted, and the resulting suspension containing leached ions caused significant cytotoxicity, revealing a substantial ionic contribution. This study indicates that both the nano-size and ionic dissolution play a significant role in the cytotoxicity of ANPs towards freshwater algae, and the exposure period largely determines the prevalent mode of nano-toxicity.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier Science.
Keywords: Aluminium Oxide Nanoparticle; Al3+ Ionic Toxicity; Hydrodynamic Size; ROS; LDH
Department/Centre: Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Depositing User: Francis Jayakanth
Date Deposited: 27 Jun 2013 07:53
Last Modified: 27 Jun 2013 07:53
URI: http://eprints.iisc.ac.in/id/eprint/46752

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