Carbon Nanopipe Dispersions in aqueous solutions and their effect on cell viability

The development of carbon nanomaterials for biomedical applications appears attractive due to their nanoscale properties although their biological profile is still in doubt. Herewith, we report that the amorphous vs crystalline character of carbon nanomaterials produced using chemical vapour deposition (CVD) in anodic alumina templates can have a marked influence on their aqueous solubility and their effect on cell viability. We prepared 250nm diameter carbon nanopipes (CNP) which were removed from the templates as loose tubes. Methods were applied to optimize the length of these pipes. Nanopipes were compared with multiwall carbon nanotubes (MWNT) for their aqueous dispersion using spectrophotometry. Carbon nanopipes and MWNT were investigated for their effect on cell viability on HeLa cells using lactate dehydrogenase (LDH) assay. Results showed that CNP remained in fine dispersion in water for at least 48h whereas MWNT precipitated during the first 2h. Surfactants had minimal effect on carbon nanopipes but variable effect on MWNT dispersion. Nanopipes remained in dispersion in cell culture media during their co-incubation for the cell viability studies. LDH assay revealed that carbon nanopipes showed substantially less cytotoxicity on HeLa cells when compared to MWNT indicating that they are a promising material for biomedical applications.