Applications and implications of nanoceria reactivity: measurement tools and environmental impact

Cerium oxide nanoparticles or nanoceria have a unique structure and interesting and unusual redox and catalytic properties that vary with the size, shape, charge, surface coating and chemical reactivity. This paper highlights applications and environmental implications of nanoceria, and describes methodologies for the assessment of the reactivity and potential toxicological effects of these particles. The physical and chemical properties in the particle design that are responsible for their reactivity and transformation in environmental and biological conditions are described. Processes such as surface oxidation, formation of surface complexes and potential interaction with redox active components of the environment are discussed. An overview of analytical characterization methods for study of nanoceria properties, reactivity and impact, highlighting methodological challenges and limitations is presented. Examples discussed include strategies to determine physicochemical properties, cytotoxicity and antioxidant or pro-oxidant activity in various exposure environments. Development of new measurement tools to facilitate rapid assessment and accelerate screening of these particles for their reactivity and effects is discussed. Future research needs for environmental assessment of benefits and potential risks associated with the use of nanoceria are also provided.