Cytotoxicity of carboxyl carbon nanotubes on human embryonic lung fibroblast cells and its mechanism

The wide use in various fields and the great potentials in biomedical applications of carbon nanotubes highlight the need to study their toxicity and biocompatibility for recent years. This work aimed to investigate the cytotoxicity of carbon nanotubes on human embryonic lung fibroblast cells and their inter-related affecting factors. Three carboxyl modified carbon nanotubes, short carboxyl single-walled carbon nanotubes (SWCNTs-COOH), short carboxyl double-walled carbon nanotubes (DWCNTs-COOH) and short carboxyl multi-walled carbon nanotubes (MWCNTs-COOH) were chosen as subjects for the evaluation of carbon nanotubes cytotoxity. Different concentrations of carboxyl carbon nanotubes were incubated with human embryonic lung fibroblast (HELF) cells for 48 h, respectively, and the electron microscopy was used to observe the cell growth and morphology. The results showed that MWCNTs-COOH, which had a better dispersion in water was much more cytotoxic than the other two carbon nanotubes. From Cell Counting Kit-8 assay and acridine orange staining, MWCNTs-COOH could inhibit the cell growth and induce cell apoptosis with a dose–effect relationship and oxidative stress may be one of the mechanisms.