Synthesis, micellization properties, and cytotoxicity trends of N-hydroxyethyl-3-alkyloxypyridinium surfactants

Abstract

N-hydroxyethyl-3-alkyloxypyridinium amphiphiles have been synthesized and characterized by various spectroscopic techniques. Self-assembling properties of these amphiphiles have been studied by surface tension, conductivity, and fluorescence measurements. Basic micellization parameters like critical micelle concentration (cmc), surface tension at the cmc (γ cmc), adsorption efficiency (pC20), effectiveness of surface tension reduction (Π cmc), maximum surface excess concentration (Γ max) and minimum surface area/molecule (A min), and Gibbs free energy of the micellization (ΔG0 mic) have also been determined. The micellization of these 3-alkyloxypyridinium halides in aqueous phase have been found to be exothermic and entropy-driven as assessed by conductivity measurements at different temperatures. Thermal degradation of these surfactants has also been assessed by thermal gravimetric analysis under nitrogen atmosphere. Further, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay of these surfactants on C6 glioma cells show them to be less toxic than conventional cationic surfactants.