Cytotoxicity of single-walled carbon nanotubes suspended in various surfactants

Abstract

The cytotoxicity of single-walled carbon nanotubes (SWCNTs) suspended in varioussurfactants was investigated by phase contrast light microscopy characterization incombination with an absorbance spectroscopy cytotoxicity analysis. Our data indicate thatindividual SWCNTs suspended in the surfactants, sodium dodecyl sulfate (SDS) andsodium dodecylbenzene sulfonate (SDBS), were toxic to 1321N1 human astrocytoma cellsdue to the toxicity of SDS and SDBS on the nanotube surfaces. This toxicity was observedwhen cells were exposed to an SDS or SDBS solution having a concentration as low as0.05 mg ml−1 for 30 min. The proliferation and viability of the cells were not affected by SWCNTs aloneor by conjugates of SWCNTs with various concentrations of sodium cholate (SC) orsingle-stranded DNA. The cells proliferated similarly to untreated cells when surrounded bySWCNTs as they grow, which indicated that the nanotubes did not affect cells adversely.The cytotoxicity of the nanotube–surfactant conjugates was controlled in these experimentsby the toxicity of the surfactants. Consequently, when evaluating a surfactant to beused for the dispersion of nanoscale materials in applications such as nanoscaleelectronics or non-viral biomolecular transporters, the cytotoxicity needs to beevaluated. The methodology proposed in this study can be used to investigate thecytotoxicity of other nanoscale materials suspended in a variety of surfactants.