Effect of anionic surfactant molecular structure on bovine serum albumin (BSA) fluorescence

The interactions of BSA with different anionic surfactants, such as sodium alkyl sulfate (CnSO4Na, n = 8, 10 and 12), sodium alkyl sulfonate (CnSO3Na, n = 8, 10 and 12) and sodium alkyl carboxylate (CnCOONa, n = 9 and 11) were investigated by fluorescence spectroscopy. The effect of molecular structure of anionic surfactants, such as the types of hydrophilic groups and the lengths of hydrophobic chain, on BSA intrinsic fluorescence was examined. It was shown that addition of anionic surfactants induced strong quenching of BSA fluorescence. The quenching of BSA fluorescence relied on the hydrophobic chain lengths of surfactant. The more hydrophobic surfactant had a greater capacity to quench BSA fluorescence. However, anionic surfactants with different headgroups did not show significant difference, e.g., CnSO4− and CnSO3− with same alkyl chain had similar quenching effect on BSA fluorescence.