Considering Nanomaterials in the Risk Assessment Paradigm: The Role of Nanoparticle Physicochemistry

Although nanotechnology is still an emerging field and the enthusiasm for the potential societal benefits of engineered nanomaterials continues, concerns are being raised about whether our knowledge of possible health risks is keeping pace with products going to market.  Some nanomaterials are being assessed for their potential hazard in occupational environments, but also are being explored for therapeutic applications.  Thus, an understanding of toxicological and biocompatible properties within a variety of exposure settings is critical.  This presentation will review the current state-of-the-science regarding the particle characteristics and exposure/dose metrics that most influence toxicity for different nanomaterials (e.g., carbon- and metal-based nanomaterials).  An overview of these nanomaterials and the characteristics which make them hazardous in one scenario and biocompatible in another will be reviewed.  Surface chemistry, peptide conjugation, and the effect of other surface chemistries and their influence on fate/transport and toxicity/biocompatibility in the body will be examined.  Characteristics of particle physicochemistry, as well as exposure metrics (e.g., particle mass, number, surface area concentrations) that have been correlated with toxicity of nanoparticles will be reviewed.   A better understanding of cellular-nanoparticle dynamics will provide a basis for toxicity testing schemes and establishing standards for protecting human health.