Cytotoxicity of Imidazole Ionic Liquids in Human Lung Carcinoma A549 Cell Line

Due to the unique property of ionic liquids (ILs), they have become attractive media for various types of chemical processes recently. ILs have become one of the hottest areas in chemistry recently. It is necessary to have a good understanding of the toxicity and environmental impact of ILs before employing them in industry on a larger scale. To enlarge the limited knowledge regarding the potential risk posed by ILs to the environment and the public, the cytotoxicities of 21 imidazole ILs were evaluated by sensitive colorimetric assay with Cell Counting Kit-8 (CCK-8), WST-8 2-(2-methoxy-4-nitro-phenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium monosodium salt) in human lung carcinoma A549 cell line. The data indicated that the toxicity of 1-alkyl-3-methylimidazolium entities was dominated by the side chain length, with the longer alkyl chain of the compound having a higher toxicity. Similar results were also found for the 1-vinylimidazole cation. At the same time, the toxicity of 1-alkyl-3-methylimidazolium and 1-vinylimidazole ionic liquid also depends on the associated anion species. The EC50 values are largest for tetrafluoroborate, whereas bis(trifluoromethylsulfonyl)imide results in the lowest EC50 value.