Induction thermal plasma process modifies the physicochemical properties of materials used for carbon nanotube production, influencing their cytotoxicity

Abstract

The effect of radio frequency induction thermal plasma (RFITP) process on the cytotoxicity of materials used for single-walled carbon nanotube production remains unknown. In this study, the influence of RFITP process on physicochemical and cytotoxic properties of commercial Co, Ni, Y₂O₃, Mo catalysts and carbon black was investigated. The cytotoxic assays (MTS, LDH, neutral red, TUNEL) revealed the strongest effect of commercial Co on murine Swiss 3T3 fibroblasts affecting their viability in a dose-dependent manner within 24 h. The cells contained also less actin stress fibres. Although RFITP affects the properties of each catalyst (size, morphology, chemistry), only cytotoxicity of Ni catalyst was increased. The plasma-treated Ni induced apoptosis. Comparing Ni particles before and after RFITP process with commercial nanoparticles of Ni revealed that the particles with similar surface area have different cytotoxicities. Interestingly, the observed toxicity of the catalysts was not mainly due to the release of ions.

Keywords::

• metallic catalyst
• nanoparticle
• proliferation
• apoptosis
• synthesis process

Acknowledgements

We thank Carl St-Louis and Sonia Blais for their help in particle characterization, Ali Shahverdi and Francis Barrette for their help in particle synthesis and Dr. Alireza Hekmat for the English proof reading of the manuscript.