Two new studies published online May 6, 2013 in the peer-reviewed scientific journal Environmental Health Perspectives researchers from the Engineered Nanomaterials Grand Opportunity (Nano GO) consortium presented their results of a project aiming to reduce interlaboratory variability. Under its framework 8 institutions carried out in vitro toxicity testing of engineered nanomaterials (ENMs) with rodent cells.
Xia and colleagues found titanium oxide to be toxic at 50ug/ml or higher and titanium dioxide to be only cytotoxic in the nanobelt form. Only the exposure to titanium dioxide did result in the presence of inflammatory markers (Xia et al.). Bonner and colleagues showed carbon nanotubes to cause inflammation in the lower lung. Carbon black nanoparticles could be made less poisonous when adding carboxyl groups or removing excess metal catalysts used in the manufacturing (Bonner et al.). Belt-shaped titanium dioxide nanoparticles caused more cellular damage to the lungs than spherical nanoparticles. In Europe, carbon black nanomaterials are authorized for food contact use with a maximum content level in food packaging of 2.5% weight/weight.
The studies showed that the toxicity of engineered nanomaterials can be best evaluated when using multiple cell types, and that mechanism-linked bioactivity assays can provide important additional information. The studies also showed that different laboratories could provide consistent results, if methods were chosen correctly. These results provide important guidance in the further safety assessment of ENMs.
Xia, T. et al. “Interlaboratory Evaluation of in Vitro Cytotoxicity and Inflammatory Responses to Engineered Nanomaterials: The NIEHS NanoGo Consortium.” Environmental Health Perspectives (published online May 6, 2013).
Bonner, J. et al. “Interlaboratory Evaluation of Rodent Pulmonary Responses to Engineered Nanomaterials: The NIEHS NanoGo Consortium.” Environmental Health Perspectives (published online May 6, 2013).