A fluorescence study of (4-{(1E,3E)-4-[4-(dimethylamino)phenyl]buta-1,3-dienyl}phenyl)methanol and its bioconjugates with bovine and human serum albumins

Abstract

Electronic absorption and fluorescence properties of (4-{(1E,3E)-4-[4-(dimethylamino)phenyl]buta-1,3-dienyl}phenyl)methanol in different media, including organic solvents of varying polarity at 298 K, an ethanol–methanol matrix at 77 K and protein environments, have been examined. The diene shows solvatochromic fluorescence, which is correlated with empirical solvent polarity parameters. The red-shifted fluorescence emission of the diene is attributed to a polar, conformationally relaxed intramolecular charge transfer excited state. Further, the diene has been covalently attached to bovine serum albumin and human serum albumin and the fluorescence probe properties of the protein-diene conjugates have been examined in phosphate buffer.