Carbon nanotubes (CNTs) are a novel synthetic material comprising only
carbon atoms. Based on its rigidity, its electrical and heat conductivity and its applicability to surface manufacturing, this material is expected to have numerous applications in industry. However, due to the material's dimensional similarity to
asbestos fibers, its carcinogenicity was hypothesized during the last decade, and indeed, we have shown that multi-wall CNTs (MWCNTs) of 50 nm in diameter are potently carcinogenic to mesothelial cells after
intraperitoneal injection. Additionally, we suggested that inflammogenicity after
intraperitoneal injection can predict mesothelial
carcinogenesis. However, few data have been published on the intraperitoneal inflammogenicity of single-wall CNTs (SWCNTs). Here, we conducted a series of studies on SWCNTs using both
intraperitoneal injection into rats and MeT5A mesothelial cells.
Intraperitoneal injection of 10 mg SWCNTs caused no remarkable
inflammation in the abdominal cavity, and the exposure of MeT5A cells to up to 25 μg/cm(2) SWCNTs did not alter proliferation. MWCNTs of 50 nm in diameter were used as a positive control, and tangled MWCNTs of 15 nm in diameter were used as a negative control. The results suggest that SWCNTs are a low-risk material with respect to mesothelial
carcinogenesis.