Spectroscopic studies on the interaction of fluorescein and safranine T in PC liposomes

In this study, the fluorescence quenching of fluorescein by safranine T in liposome media had been investigated systematically by fluorescence spectroscopy. UV-vis absorption spectroscopy and fluorescence decay lifetime measurements. The spectroscopic data were analyzed using a Stern-Volmer equation to determine the quenching process. The experimental results showed that the intrinsic fluorescence of fluorescein was strongly quenched by safranine T, and that the quenching mechanism was considered as static quenching by forming a ground-complex. The Stern-Volmer quenching constant K-sv and the bimolecular quenching constant K-q were estimated. The distances between the donor (fluorescein) and the acceptor (safranine T) were calculated according to the Forster non-radiation energy transfer theory. In addition, the partition coefficient of the safranine T (K-p) in the L-egg lecithin phosphatidylcholine liposomes was also calculated by utilizing the fluorescence quenching. (C) 2012 Elsevier B.V. All rights reserved.