Nanotoxicity: emerging concerns regarding nanomaterial safety and occupational hard metal (WC-Co) nanoparticle exposure

Abstract

As the number of commercial and consumer products containing engineered nanomaterials (ENMs) continually rises, the increased use and production of these ENMs presents an important toxicological concern. Although ENMs offer a number of advantages over traditional materials, their extremely small size and associated characteristics may also greatly enhance their toxic potentials. ENM exposure can occur in various consumer and industrial settings through inhalation, ingestion, or dermal routes. Although the importance of accurate ENM characterization, effective dosage metrics, and selection of appropriate cell or animal-based models are universally agreed upon as important factors in ENM research, at present, there is no “standardized” approach used to assess ENM toxicity in the research community. Of particular interest is occupational exposure to tungsten carbide cobalt (WC-Co) “dusts,” composed of nano- and micro-sized particles, in hard metal manufacturing facilities and mining and drilling industries. Inhalation of WC-Co dust is known to cause “hard metal lung disease” and an increased risk of lung cancer; however, the mechanisms underlying WC-Co toxicity, the inflammatory disease state and progression to cancer are poorly understood. Herein, a discussion of ENM toxicity is followed by a review of the known literature regarding the effects of WC-Co particle exposure. The risk of WC-Co exposure in occupational settings and the updates of in vitro and in vivo studies of both micro- and nano-WC-Co particles are discussed.

Keywords:

• engineered nanomaterial
• occupational exposure
• lung disease
• cancer
• toxicity
• particle

Acknowledgments

We acknowledge the financial support from WV NASA EPSCoR, AO Foundation (Project S-13-15L), Osteosynthesis and Trauma Care Foundation, and Orthopaedic Research and Education Foundation. Fellowship funding to A. Armstead was provided by the West Virginia University NANOSAFE graduate fellowship program 2010–12 (formerly WVNano; NSF Cooperative Agreement #1003907) and by the American Foundation for Pharmaceutical Education (Pre-Doctoral Fellowship in Pharmaceutical Science, 2012–14). The authors acknowledge the WVU Flow Cytometry Core facility, operated by Kathy Brundage, which is supported by the National Institutes of Health equipment grant number S10OD016165 and the Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant numbers P30GM103488 (CoBRE) and P20GM103434 (INBRE).

Disclosure

The authors report no conflicts of interest in this work.