Carboxylated nanodiamonds are neither cytotoxic nor genotoxic on liver, kidney, intestine and lung human cell lines

Abstract

Although nanodiamonds (NDs) appear as one of the most promising nanocarbon materials available so far for biomedical applications, their risk for human health remains unknown. Our work was aimed at defining the cytotoxicity and genotoxicity of two sets of commercial carboxylated NDs with diameters below 20 and 100 nm, on six human cell lines chosen as representative of potential target organs: HepG2 and Hep3B (liver), Caki-1 and Hek-293 (kidney), HT29 (intestine) and A549 (lung). Cytotoxicity of NDs was assessed by measuring cell impedance (xCELLigence® system) and cell survival/death by flow cytometry while genotoxicity was assessed by γ-H2Ax foci detection, which is considered the most sensitive technique for studying DNA double-strand breaks. To validate and check the sensitivity of the techniques, aminated polystyrene nanobeads were used as positive control in all assays. Cell incorporation of NDs was also studied by flow cytometry and luminescent N–V center photoluminescence (confirmed by Raman microscopy), to ensure that nanoparticles entered the cells. Overall, we show that NDs effectively entered the cells but NDs do not induce any significant cytotoxic or genotoxic effects on the six cell lines up to an exposure dose of 250 µg/mL. Taken together these results strongly support the huge potential of NDs for human nanomedicine but also their potential as negative control in nanotoxicology studies.

• Confocal and Raman microscopy
• cytotoxicity
• flow cytometry
• genotoxicity
• impedancemetry
• nanodiamonds

Acknowledgements

The authors would like to thank A. Crisci for the Raman experiments.

Declaration of interest

The authors declare that they have no competing financial interests. This study was funded by the French national research program NANOTRANS, the NanoSciences CEA-Transverse program, Dim C’Nano idf, the French Agency for Food, Environmental and Occupational Health Safety ANSES and the European Commission [BOOSTER project (BiO-dOSimetric Tools for triagE to Responders), project number 242361, call number SEC-2009-4.3-02].

Supplementary material available online Supplementary 1–7