Internalization of carbon black and maghemite iron oxide nanoparticle mixtures leads to oxidant production.

The risk of potential human exposure to mixed nanomaterials in consumer, occupational, and medicinal settings is increasing as nanomaterials enter both the workplace and the marketplace. In this study, we investigated the toxicity of mixed engineered carbon black (ECB) and maghemite iron oxide (Fe(2)O(3)) nanoparticles in a cellular system to understand the mechanism of toxicity and potential methods of toxicity mitigation. Lung epithelial cells (A549) were exposed to mixed Fe(2)O(3) and ECB nanoparticles, mixed Fe(2)O(3) and ECB nanoparticles with the addition of L-ascorbic acid, and mixed Fe(2)O(3) and surface-oxidized engineered carbon black (ox-ECB) nanoparticles.