In vitro toxicity of amorphous silica nanoparticles in human colon carcinoma cells

Abstract

The use of nanostructured silica (SiO₂) particles is no longer restricted to biomedical and (bio-) technological fields but rather finding applications in products of the food industry. Thus, our studies on the toxicological relevance of SiO₂ nanoparticles focused on cytotoxic effects, the modulation of the cellular redox status and the impact on DNA integrity in human colon carcinoma cells (HT29). The results indicate that these SiO₂ nanoparticles stimulate the proliferation of HT29 cells, depending on the incubation time and the particle size. The cytotoxicity of the investigated SiO₂ nanoparticles was found to depend on the concentration, size and on the FCS content of the culture medium. Furthermore, SiO₂ seem to interfere with glutathione biosynthesis. The results indicate further that effects of SiO₂ NPs are not mediated by oxidative stress but by interference with the MAPK/ERK1/2 as well as the Nrf2/ARE signalling pathways. Additionally, investigations regarding DNA integrity revealed no substantial (oxidative) DNA damage.

Keywords::

• Cellular uptake
• cytotoxicity
• proliferation
• glutathione
• particle agglomeration

Acknowledgements

This work was partly funded by the Karlsruhe Institute of Technology (KIT) via the competence area of Applied Life Sciences.