Determining the cytotoxicity of catanionic surfactant mixtures on HeLa cells

The cytotoxicity of commonly used synthetic surfactants and catanionic mixts. of those was evaluated using MTT on HeLa cells. The 50% inhibition concn. (IC50) for MTT redn. was calcd. The effect on chain length increase and inclusion of polyoxyethylene groups on the toxicity was tested on single surfactant systems. A general trend of increasing toxicity with increasing chain length and the presence of polyoxyethylene groups was obsd. The measured IC50 values of catanionic systems lie between those of participating surfactants. The increase in toxicity as the cationic surfactant is added to the anionic one is however not linear. A steep decrease of the IC50 values (and therefore increase in the toxic properties) is obsd. immediately already at low concns. of the cationic surfactants. This behavior is analogous to the enzyme activity in catanionic microemulsions