Characterization of mixed micelles of cationic twin tail surfactants with phospholipids using fluorescence spectroscopy

The pyrene fluorescence measurements have been carried out for various binary mixtures of micelle forming (L-α-diheptanoylphosphatidycholine, DHPC) and vesicle forming (L-α-dimyristoylphosphatidycholine, DMPC) phospholipids with different twin tail alkylammonium surfactants. The mixed micelle formation in all binary mixtures has been evaluated and it has been observed that the mixed micelle formation between the unlike components of phospholipid and cationic surfactants takes place due to the synergistic interactions. The influence of hydrophobicity of series of twin tail cationic surfactants has been studied on the degree of synergism.

The pyrene fluorescence measurements have been carried out for various binary mixtures of micelle forming (L-α-diheptanoylphosphatidycholine, DHPC) and vesicle forming (L-α-dimyristoylphosphatidycholine, DMPC) phospholipids with different twin tail alkylammonium surfactants with and without spacer. It has been found that increase in the hydrophobicity of both twin hydrocarbon tails as well as that of spacer, generates stronger synergism with DHPC. In contrast, synergism decreases with an increase in the hydrophobicity of both hydrocarbon twin tails and spacer length in the mixed micelles of DMPC. The origin of synergism of both phospholipids with present cationic surfactants can only be attributed to an identical mechanism that is the reduction in polar head group repulsions.Figure optionsDownload as PowerPoint slide