1-Naphthol as an excited state proton transfer fluorescent probe for erythrocyte membranes

The microenvironmental dependence of excited state prototropism of I-naphth ol and the corresponding changes in its fluorescence emission is utilized t o monitor the acyl chain melting phase transition behavior of liposome memb rane made from human erythrocyte lipids. A sharp increase in the ratio of n eutral/anionic form fluorescence intensity is noticed at the phase transiti on temperature (19 degrees C). This provides a convenient method for obtain ing phase transition temperature in lipid membranes. The membrane modifying effect of cholesterol on the erythrocyte liposome is successfully sensed b y I-naphthol fluorescence. (C) 2000 Elsevier Science B.V. All rights reserv ed.