NIST gold nanoparticle reference materials do not induce oxidative DNA damage

Abstract

One primary challenge in nanotoxicology studies is the lack of well-characterised nanoparticle reference materials which could be used as positive or negative nanoparticle controls. The National Institute of Standards and Technology (NIST) has developed three gold nanoparticle (AuNP) reference materials (10, 30 and 60 nm). The genotoxicity of these nanoparticles was tested using HepG2 cells and calf-thymus DNA. DNA damage was assessed based on the specific and sensitive measurement of four oxidatively-modified DNA lesions (8-hydroxy-2´-deoxyguanosine, 8-hydroxy-2´-deoxyadenosine, (5´S)-8,5´-cyclo-2´-deoxyadenosine and (5´R)-8,5´-cyclo-2´-deoxyadenosine) using liquid chromatography/tandem mass spectrometry. Significantly elevated, dose-dependent DNA damage was not detected at concentrations up to 0.2 μg/ml, and free radicals were not detected using electron paramagnetic resonance spectroscopy. These data suggest that the NIST AuNPs could potentially serve as suitable negative-control nanoparticle reference materials for in vitro and in vivo genotoxicity studies. NIST AuNPs thus hold substantial promise for improving the reproducibility and reliability of nanoparticle genotoxicity studies.

Keywords::

• DNA damage
• genotoxicity
• gold nanoparticles
• mass spectrometry
• reference materials

Acknowledgements

The authors acknowledge and thank Miral Dizdaroglu of NIST for his scientific advice and assistance with the DNA damage data interpretation. The authors would like to thank Teresa Butler, Vince Hackley, Stephen E. Long and Michael Winchester of NIST for providing the AuNP RMs for the reported experiments and/or for helping to characterise the RMs in the calf-thymus DNA incubation samples. In addition, we would like to thank Alessandro Tona of NIST for culturing the HepG2 cells for the 24 h DNA damage portion of the study.