Nanoparticle reactivity toward dithiothreitol

Abstract

Hazard determination of nanoparticles (NP) is challenging and should be based on a predictive and pragmatic tier approach. The biological effects of NP appear to be related not only to surface/size but also to their ability to generate free radicals/oxidants. We propose that the measurement of this property by acellular assays could be helpful for NP toxicity screening. This study investigated the effect of dispersing conditions on the oxidative capacity of a small selection of carbonaceous NP toward dithiothreitol (DTT). Increasing surfactant concentration decreased the DTT reactivity on these studied particles. Afterward, a panel of NP were studied under constant conditions. Classification of the NP panel based on their DTT reactivity was found to be dependent on the metric used (mass or surface) but not on the surfactant type. The DTT assay may be useful for an initial evaluation of the hazardousness of manufactured or unintentionally produced NP. However, the predictive potential of such a test towards biological effects still needs to be evaluated.

• Dithiothreitol
• surfactant
• reactivity
• carbon black
• diesel
• nanoparticles

Acknowledgements

This study was supported by the Agence Française de Sécurité Sanitaire de l'Environnement et du Travail (AFSSET) Grant EST-2006/1/7. We would like to thank Nadège Gavillet and Magdalena Sanchez for their excellent practical work, Dr Michel Bonin from the Centre de Microscopie de l'Université de Lausanne for the TEM measurements and Dr Edy Casali from Polytechnic School of Lausanne for BET measurements. We thank Prof. Francelyne Marano and Dr Michel Rossi for the gracious gift of TiO₂ and CB, respectively, as well as Dr Lucienne Juillerat for helpful comments on this manuscript.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.