The Vital Role of Buffer Anions in the Antioxidant Activity of CeO₂ Nanoparticles

Abstract

Cerium oxide (CeO(2)) nanoparticles display excellent antioxidant properties by scavenging free radicals. However, some studies have indicated that they can cause an adverse response by generating reactive oxygen species (ROS). Hence, it is important to clarify the factors that affect the oxidant/antioxidant activities of CeO(2) nanoparticles. In this work, we report the effects of different buffer anions on the antioxidant activity of CeO(2) nanoparticles. Considering the main anions present in the body, Tris-HCl, sulfate, and phosphate buffer solutions have been used to evaluate the antioxidant activity of CeO(2) nanoparticles by studying their DNA protective effect. The results show that CeO(2) nanoparticles can protect DNA from damage in Tris-HCl and sulfate systems, but not in phosphate buffer solution (PBS) systems. The mechanism of action has been explored: cerium phosphate is formed on the surface of the nanoparticles, which interferes with the redox cycling between Ce(3+) and Ce(4+). As a result, the antioxidant activity of CeO(2) nanoparticles is greatly affected by the external environment, especially the anions. These results may provide guidance for the further practical application of CeO(2) nanoparticles.

Evaluation of the oxidase like activity of nanoceria and its application in colorimetric assays

“…Since the catalytic properties of NPs are highly dependent on the pH of the reaction medium and buffer anions [39], it was important to investigate the effect of these parameters. Figure S3 shows the effect of pH on dopamine oxidation for a nanoceria dispersion in the pH range from 6 to 8 in PBS.…”

Environmental release, fate and ecotoxicological effects of manufactured ceria nanomaterials

“…The calculation of Ce (III):Ce(IV) ratios was performed, 48 in an analogous manner to EELS, within a multi-method approach. Similarly, synchrotron-based X-ray spectroscopy has been used in several studies to assess Ce speciation.…”

An electrochemical DNA biosensor for evaluating the effect of mix anion in cellular fluid on the antioxidant activity of CeO2 nanoparticles

“…1E), which proved further the aggregation of the CeO 2 nanoparticles. It has been proved that the aggregation in that degree has no effect on the antioxidant properties of the particles (Xue et al, 2011(Xue et al, , 2012.…”

“…It is believed that antioxidant activity of CeO 2 nanoparticles was affected by external anions (Singh et al, 2011;Xue et al, 2012). As significant part of internal environment, four main anions exist in intracellular fluid and intercellular fluid.…”

“…However, all those factors affected the antioxidant activity of CeO 2 nanoparticles in a limited degree, and they were not the key factor for the loss of antioxidant activity of CeO 2 nanoparticles. It was found that the antioxidant activity of the nanoparticles was susceptible to external anions, and the influences depended on the anion type (Singh et al, 2011;Xue et al, 2012). PO 4 3 À could make CeO 2 nanoparticles lose antioxidant activity by forming cerium phosphate on the particles' surface.…”