Most recent scientific efforts have focused on examining toxicities of manufactured nano-particles (MNPs) only in source materials. By not evaluating MNPs at the point of exposure, these efforts fail to address the relevant question of whether or not consumer-product-derived MNPs are of concern to public health and the environment. The proposed US-UK consortium, ‘Risk Assessment for Manufactured Nanoparticles Used in Consumer Products (RAMNUC)’, provides a systematic, multidisciplinary approach, including both experimental and computational tools and projects, for predicting potential human and environmental risks associated with the use of selected consumer products that respectively incorporate zinc oxide, silver, and cerium dioxide nanoparticles.
The overall hypothesis of the RAMNUC project is that MNPs at the point of exposure for both humans and aquatic animals will substantially differ in both physicochemical and toxicological properties from MNPs at the source (synthesized in the laboratory or acquired commercially). These differences may have significant consequences with respect to MNPs’ bioavailability, alterations of immunity, induction of oxidative stress, inflammation, disease processes, and other toxicity measures.
We will assess intracellular and extracellular bioavailability and toxicity of the selected MNPs, as synthesized and as incorporated in consumer products, using both in vitro and in vivo experiments. Tested MNPs will be controlled or well characterized for their physical (e.g., size, shape, state of agglomeration/aggregation) and chemical properties (e.g., composition, functionalization, surface chemistry).
Our proposed in vitro and in vivo studies will produce mechanism-based results relating toxic effects to MNP physicochemical properties. The RAMNUC Consortium will also include a novel human exposure simulation study that will produce realistic estimates of MNP exposures to consumers. Data generated from these mechanistic experiments will be integrated into the mechanism-based computational modules of two existing source-to-exposure-dose-to-effects modeling systems, allowing for rational extrapolation and generalization in MNP risk assessment. Built upon the inter-institutional expert structure, the RAMNUC consortium serves as a model for systematically addressing complex problems associated with MNP risk assessment and will generate results that will contribute to our very limited knowledge about health risks associated with the use of nanotechnology based consumer products.