Safety Evaluation of Silver Nanoparticles: Inhalation Model for Chronic Exposure

摘要

The rapid emergence of nanotechnology including production of engineered nanoparticles is likely to provide our society with a continuous range of consumer products with advanced technology applications. Among the 580 consumer products containing known nanomaterials, the most common material is silver-based nanoparticles. Human exposure likelihood and needed risk exposure analysis to these product-derived nanomaterials are now required for every age level. Further, disposal and degradation of these products and release from engineered sources has an indirect human exposure potential and an environmental impact concern. The approach to assess toxicity of nanomaterials is a new and evolving field. Most nanotoxicology studies have focused on mechanistic understanding using in vitro models with the early reports demonstrating that high levels of silver nanoparticles are lethal to eukaryotic cell-based systems. Nanotoxicology assessment studies performed in vivo using appropriate dosing amounts and routes of exposure carry greater significance because of the diversity of systemic phenotypic response and the physiologic/anatomic influence that can be translatable from animal models to human exposures. Particle pharmacokinetics and dynamics of nondissolved solution materials combined with issues of regional dissolution rates can provide the true impact of dosing on systemic physiology and positional anatomy. The present information on silver nanoparticle toxicity in vivo has been limited. More importantly, there remains a need to differentiate between soluble/ionic forms of silver in tissues or a test for the presence of insoluble salts. Thus the distribution of silver nanoparticle after inhalation will require much more information to delineate distribution kinetics/dynamics, toxicity processes, and define key mechanisms for the effects observed.