Toxicity of CeO2 nanoparticles – The effect of nanoparticle properties

• Published in: Journal of photochemistry and photobiology. B, Biology Vol. 145; pp. 48 - 59
• Main Authors: Leung, Yu Hang, Yung, Mana M.N., Ng, Alan M.C., Ma, Angel P.Y., Wong, Stella W.Y., Chan, Charis M.N., Ng, Yip Hang, Djurišić, Aleksandra B., Guo, Muyao, Wong, Mabel Ting, Leung, Frederick C.C., Chan, Wai Kin, Leung, Kenneth M.Y., Lee, Hung Kay
• Format: Journal Article
• Language: English
• Published: Switzerland Elsevier B.V 01.04.2015
• Subjects: Cerium - chemistry; Diatoms - drug effects; Diatoms - radiation effects; Electron Spin Resonance Spectroscopy; Escherichia coli - drug effects; Escherichia coli - radiation effects; Metal Nanoparticles - chemistry; Metal Nanoparticles - toxicity; Metal Nanoparticles - ultrastructure; Microscopy, Electron, Scanning; Ultraviolet Rays
• ISSN: 1011-1344; 1873-2682
• DOI: 10.1016/j.jphotobiol.2015.01.017

•Different toxicity observed on different CeO2 nanostructured samples.•Nanostructure compositions and interactions with cells are likely the causes.•Toxicity tests on bacteria only may not be suitable for predicting the ecotoxicity. Conflicting reports on the toxicity of CeO2 nanomaterials have been published in recent years, with some studies finding CeO2 nanoparticles to be toxic, while others found it to have protective effects against oxidative stress. To investigate the possible reasons for this, we have performed a comprehensive study on the physical and chemical properties of nanosized CeO2 from three different suppliers as well as CeO2 synthesized by us, and tested their toxicity. For toxicity tests, we have studied the effects of CeO2 nanoparticles on a Gram-negative bacterium Escherichia coli in the dark, under ambient and UV illuminations. We have also performed toxicity tests on the marine diatom Skeletonema costatum under ambient and UV illuminations. We found that the CeO2 nanoparticle samples exhibited significantly different toxicity, which could likely be attributed to the differences in interactions with cells, and possibly to differences in nanoparticle compositions. Our results also suggest that toxicity tests on bacteria may not be suitable for predicting the ecotoxicity of nanomaterials. The relationship between the toxicity and physicochemical properties of the nanoparticles is explicitly discussed in the light of the current results.