Logically sensing aggregate process and discriminating SDS from other surfactants with the assistance of BSA

An amphiphilic fluorescent probe, 3-dodecylamino dihydrogen imidazo[2,1-α]benz[de]isoquinolin-7-one (compound 3), was used to sense the aggregate formation process of bovine serum albumine (BSA), sodium dodecyl sulfate (SDS) and their mixed system. The fluorescence intensity of 3 was significantly affected by the adding order of SDS and BSA, and SDS can be distinguished from other surfactants with the aid of BSA, but only when 3 is allowed to interact with BSA first. The results revealed that compound 3 is preferentially sited in the hydrophobic region of BSA, and thermodynamically in SDS-BSA mixed aggregate. Sodium phosphate buffer solution (PBS) and BSA played important but distinct roles in distinguishing SDS micelle from the others.