Cellular toxicity evaluation of helical rosette nanotubes

Helical rosette nanotubes (HRN) are synthesized through the molecular self-assembly of individual rosette compounds. HRN are water-soluble and synthesized in the absence of any metals. They have a range of potential applications including drug delivery. We have evaluated the potential in vitro toxicity of the HRN-K1 compound in the Calu-3 pulmonary epithelial cell line. Cells were treated with: Control (media only), Lysine (25\u3bcg/cm), 2.5, 12.5, 25\u3bcg/cm\ub2 of HRN-K1 (HRN with lysine residue), 200\u3bcg/cm\ub2 and 60\u3bcg/cm\ub2 of quartz. Lysine and quartz were used as controls. Cells and supernatant samples were collected for analysis at 1, 12, and 24h post-treatment. Cell viability was determined using Trypan Blue counting and a reduction in viability was detected in the high dose quartz group only. A gel electrophoresis assay showed DNA shearing in the high dose quartz group only. Preliminary ELISA data on cell supernatant indicate the release of IL-8 in the quartz groups and 25\u3bcg/cm\ub2 HRN-K1 group at 12 & 24h compared to media-only control. Real time quantitative Rt-PCR has also been performed for IL-8, TNF-\u3b1 and ICAM-1. In conclusion, HRN-K1 does not reduce Calu-3 cell viability or induce DNA strand breakage, but may activate cytokine release in vitro. These results contrast studies demonstrating cytotoxicity using single-walled carbon nanotubes in vitro.(Support: NSERC NanoIP to B.S. and CIHR Doctoral Award to W.S.J.)Peer reviewed: YesNRC publication: Ye