Cerium oxide nanoparticles, so-called nanoceria, are engineered nanomaterials prepared by many methods that result in products with varying physicochemical properties and applications. Those used industrially are often calcined, an example is NM-212. Other nanoceria have beneficial pharmaceutical properties and are often prepared by solvothermal synthesis. Solvothermally synthesized nanoceria dissolve in acidic environments, accelerated by carboxylic acids. NM-212 dissolution has been reported to be minimal. To gain insight into the role of high-temperature exposure on nanoceria dissolution, product susceptibility to carboxylic acid-accelerated dissolution, and its effect on biological and catalytic properties of nanoceria, the dissolution of NM-212, a solvothermally synthesized nanoceria material, and a calcined form of the solvothermally synthesized nanoceria material (ca. 40, 4, and 40 nm diameter, respectively) was investigated. Two dissolution methods were employed. Dissolution of NM-212 and the calcined nanoceria was much slower than that of the non-calcined form. The decreased solubility was attributed to an increased amount of surface Ce4+ species induced by the high temperature. Carboxylic acids doubled the very low dissolution rate of NM-212. Nanoceria dissolution releases Ce3+ ions, which, with phosphate, form insoluble cerium phosphate in vivo. The addition of immobilized phosphates did not accelerate nanoceria dissolution, suggesting that the Ce3+ ion release during nanoceria dissolution was phosphate-independent. Smaller particles resulting from partial nanoceria dissolution led to less cellular protein carbonyl formation, attributed to an increased amount of surface Ce3+ species. Surface reactivity was greater for the solvothermally synthesized nanoceria, which had more Ce3+ species at the surface. The results show that temperature treatment of nanoceria can produce significant differences in solubility and surface cerium valence, which affect the biological and catalytic properties of nanoceria.
Digital Object Identifier (DOI)
The research leading to these results received funding from the National Institutes of Health [grant agreement No R01GM109195] and the PATROLS project, as part of European Union’s Horizon 2020 research and innovation program [grant agreement No 760813].
Yokel, Robert A.; Wohlleben, Wendel; Keller, Johannes Georg; Hancock, Matthew L.; Unrine, Jason M.; Butterfield, D. Allan; and Grulke, Eric A., "The Preparation Temperature Influences the Physicochemical Nature and Activity of Nanoceria" (2021). Pharmaceutical Sciences Faculty Publications. 164.
Supporting Information File 1: Additional experimental data
2190-4286-12-43-presentation.png (8786 kB)
Picture with graphical abstract, title and authors for social media postings and presentations
Chemicals and Drugs Commons, Nanotechnology Commons, Pharmacy and Pharmaceutical Sciences Commons
Published in Beilstein: Journal of Nanotechnology, v. 12.
© 2021 Yokel et al.; licensee Beilstein-Institut.
This is an Open Access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0). Please note that the reuse, redistribution and reproduction in particular requires that the author(s) and source are credited and that individual graphics may be subject to special legal provisions.
The license is subject to the Beilstein Journal of Nanotechnology terms and conditions: (https://www.beilstein-journals.org/bjnano/terms).