Using Nanoparticles As Antioxidants

By incubating them with electron donors, scientists have managed to improve the antioxidant ability of nanoceria.

AsianScientist (Feb. 12, 2015) – Scientists have developed nanoparticles that can act as synthetic antioxidants in the body, allowing them to potentially treat diseases caused by reactive oxygen species that upset the normal redox balance. Their results have been published in Angewandte Chemie.

Nanoparticles of cerium oxide (nanoceria) make good catalysts because of the presence of mixed valence states of cerium and oxygen vacancies. In additon, it has been reported that nanoceria has extraordinary antioxidant activity that makes it suitable as a therapeutic agent for several diseases including cancer, neurodegenerative diseases, diabetes and atherosclerosis.

However, the inherent superoxide (SOD) scavenging ability has only been found in nanoceria with sizes of less than five nm. Furthermore, bioactive nanoceria show very limited diversity with respect to shape, thereby limiting their applications.

Led by Professor Zhang Zhiyong, a team of researchers from the Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, the Institute of High Energy Physics, Chinese Academy of Sciences, collaborated with Professor Yin Junjie of the US Food and Drug Administration to study the relationship between the physicochemical characteristics of nanoceria and its SOD scavenging ability.

The researchers found that the nanoceria they used, with a size of 5.1±0.4 nm, exhibited a negligible Ce3+/Ce4+ ratio and very low SOD mimetic activity. But when incubated with Copper, Zinc-SOD or other electron donors, the SOD mimetic activity of nanoceria could be activated within minutes.

The activity of the nanoceria could be repeatedly regenerated or maintained for a long time when there was continuous electron transfer. This method will make it possible to develop nanoceria-based superoxide-scavengers with long-acting activity and tailorable characteristics, paving the way for more practical and attractive biomedical applications for nanoceria.

The article can be found at: Li et al. (2014) Acquired Superoxide-Scavenging Ability of Ceria Nanoparticles.


Source: Chinese Academy of Sciences.
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