Human Health Impacts and Immunotoxicology of Metal Nanoparticles and Nanomaterials – An Overview

The ubiquitous use of engineered nanomaterials in consumer products, occupational settings, and biomedical applications has become more commonplace. Many of these nanomaterials contain metals or metal oxides. Although the health effects of metals in humans has been well-documented for decades, the effects of metals and metal oxides as nanoparticles is less understood. A large body of research already exists on these particular applications, and more information emerges every day. One particular aspect of human exposure to metal nanoparticles involves effects on the immune system. Metal nanoparticles have the potential to elicit a strong immune response, including immunosuppression; inflammation and autoimmunity; and sensitivity and hypersensitivity reactions. Immune-triggered human health effects of metal and metal oxide nanoparticles evolve from cellular mechanisms of injury, such as oxidative stress; interactions with cellular membranes and proteins; and disruption of signaling pathways. Much of the expected effects of metal nanoparticles on human health can be extrapolated from surrogate exposures, primarily urban air pollution and welding fumes. As this trend of utilizing metals and metal oxides on the nanoscale for commercial and industrial applications continues, it will increasingly become more important to apply gained knowledge of anticipated outcomes of exposures to these particles and how to mitigate their effects in human populations.