Preparation and characterization challenges to understanding environmental and biological impacts of ceria nanoparticles

Increasingly, it is recognized that understanding and predicting nanoparticle behavior are often limited by the reliability and reproducibility of the production methods as well as the extent to which they are adequately characterized. Two examples are used to demonstrate how sample preparation methods and processing history may significantly impact particle behavior: (1) an examination of cerium oxide (ceria) particles reported in the literature in relation to the biological responses observed and (2) observations showing the influence of synthesis details on the aging of ceria nanoparticles. Examining data from the literature for ceria nanoparticles suggests that thermal history is one factor that has a strong influence on biological impact. Thermal processing may alter many physicochemical properties of the particles, including density, crystal structure, and the presence of surface contamination. However, these properties may not be sufficiently recorded or reported to determine the ultimate source of an observed impact. A second example shows the types of difficulties that can be encountered in efforts to apply a well-studied synthesis route to producing well-defined particles for biological studies. These examples and others further highlight the importance of characterizing particles thoroughly and recording details of particle processing and history that too often are underreported. Copyright (c) 2012 John Wiley & Sons, Ltd.