Effect of biocompatible gluconamide-type cationic surfactants on thermotropic phase behavior of phosphatidylcholine/cholesterol bilayers

• Interaction of new sugar-derived cationic surfactants with artificial membranes by DSC.
• Toxicity with respect to L929 mouse fibroblast and A549 human lung cancer cells.
• The effect of the gluconamide moiety on cytotoxicity.
• Computations of molecular properties important in interactions with membrane.

A series of soft cationic surfactants, containing a saccharide-derived moiety in their hydrophilic grouping – 2-(alkyldimethylammonio) ethylgluconamide bromides, denoted as CnGAB, n = 10, 12, 14 and 16 – were analyzed with respect to their influence on the thermotropic phase behavior of phosphatidylcholine (DPPC)/cholesterol bilayers. The compounds were found to be uniformly distributed in the studied lipid bilayer. As usual, the longer the chain of CnGAB, the stronger was the effect on Tm and ΔHm, except C16GAB. Having the longest chain, C16GAB reduces Tm to the smallest extent and does not affect ΔHm until the molar ratio of surfactant/DPPC is 0.15. The interactions with model cells in vitro were determined by cytotoxicity evaluation with respect to two cell lines – mouse fibroblast cell line L929 and human lung cancer cell line A549. The toxicity of CnGABs is much lower than a classical DTAB.