Environmental Science: Nano Blog

Nanoceria (nanoparticle form of CeO₂, cerium(IV) oxide) is quickly becoming a trending topic in Environmental Science. After recently discussing its health effects, today we present a fascinating paper regarding its biodistribution and retention in rats.

Currently, the main use for nanoceria is as an abrasive catalyst, especially important for the industry in silicon integrated circuit fabrication. In addition to that, and thanks to its autocatalytic behaviour, encouraging results have been presented in the past regarding its use as an antineoplastic agent. Nevertheless, there is concern on the topic of its toxicity in organisms.

Dr Robert A. Yokel and colleagues from the University of Kentucky have conducted an extensive investigation on the distribution and retention of several nanocerias after their systemic administration to rats.

The aim of their study was to determine if and how the biodistribution and persistence of nanocerias are modified according to the doses administered.

Additionally, interesting discussions regarding nanoceria shape and its influence on its toxicity, retention and disposition have been presented.

Moving forward, it will be exceptionally exciting to learn more about nanoceria’s clinical properties and effects on animals. In any case, this work is a big step forward in its research, helping us to clarify and consolidate our knowledge of the behaviour of nanocerias in mammalian organisms.

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Nanoceria biodistribution and retention in the rat after its intravenous administration are not greatly influenced by dosing schedule, dose, or particle shape
Robert A. Yokel, Jason M. Unrine, Peng Wu, Binghui Wang and Eric A. Grulke
Environ. Sci.: Nano, 2014, Advance Article
DOI: 10.1039/C4EN00035H

The paper mentioned today is part of our Nanoceria Research themed collection, which is the most comprehensive and current source of information on the chemistry, biology, and beneficial and untoward effects of nanocerias.

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Nanomaterials have shown such great potential to advance science and engineering that sometimes research on their applications can skip ahead of safety tests.

Nanoceria, a commonly used nanomaterial, is one such substance. These fine grains of cerium oxide have been proposed for use in fuels, sunscreens, and even pharmaceutical treatments, but the effects of long-term exposure have not been comprehensively investigated. Now, in a critical review published in Environmental Science: Nano’s themed issue, a team of pharmacists and environmental chemists have compiled and analyzed the available research on nanoceria’s health effects.

Nanoceria appears to have minimal effects when applied to the skin, and is not absorbed into the body through the digestive tract. However, once it makes its way into the bloodstream, whether through inhalation or direct injection, it can travel throughout the body.

Nanoceria is biopersistent, meaning that it does not dissolve or break down in the body, but instead builds up. When it finds its way into certain organs—such as the lungs or the liver—it can take months to completely leave, and can lead to inflammation and abnormal tissue growth. As with many hazardous materials, the risks are greater with higher doses or longer-term exposure.

The researchers propose that nanoceria’s toxic effects occur through inducing oxidative stress, an imbalance between oxidizing molecules and antioxidants that can disrupt biochemical pathways in the body. Because the surface properties of nanomaterials are believed to have the greatest influence on their potential toxicity, the authors suggest that coating the particles with a biologically inert material or altering their surface structure could reduce their impacts.

Nanoceria should not be indiscriminately avoided based on these findings—and some research has found positive biological applications for the substance, and even essential chemicals like water can be toxic in high enough doses. Rather, scientists working with these particles should understand their potential risks and work to minimize them.

To access the full article, download a copy for free* by clicking the link below.

The yin: an adverse health perspective of nanoceria: uptake, distribution, accumulation, and mechanisms of its toxicity
DOI: 10.1039/c4en00039k
R. Yokel et al.

Liked this blog? Find out more about Laurel in her first Environmental Science: Nano blog on rare earth elements.

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