A study on the interactions of surfactants with phospholipid/polydiacetylene vesicles in aqueous solutions

A colorimetric method for studying the interactions of surfactants with lipid vesicles, formed from dimyristoylphosphatidycholine (DMPC) and polymerized 10,12-pentacosadiynoic acid (PCDA), in aqueous solutions was reported. The electrostatic interaction and hydrophobic interaction play a key role in the interaction of the mixed lipid vesicles with surfactant. The hydrophobic interaction results in the insertion of the alkyl chain of surfactants into the hydrophobic domain of the vesicles. The insertion perturbs the conformation of the polymerized PCDA backbone in the mixed vesicles, which induces the chromatic response. The value of chromatic response induced by the addition of surfactants was found to correlate with the DMPC content in the vesicles; an increase of DMPC content would enhance the interaction of surfactants with the mixed vesicles.