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

Abstract A series of soft cationic surfactants, containing a saccharide-derived moiety in their hydrophilic grouping – 2-(alkyldimethylammonio) ethylgluconamide bromides, denoted as C n GAB, 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 C n GAB, the stronger was the effect on T m and Δ H m , except C 16 GAB. Having the longest chain, C 16 GAB reduces T m to the smallest extent and does not affect Δ H m 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 C n GABs is much lower than a classical DTAB.