Surfactant modulation effect on the fluorescence emission of a dual-fluorophore: Realizing a single discriminative sensor for identifying different proteins in aqueous solutions

Abstract

A bispyrene-modified perylene derivative (PEPBI), in which the pyrene and the perylenebisimide were connected by a hydrophilic oligoethoxy linker, was designed and synthesized. The absorption spectra and emission spectra revealed that PEPBI has the characteristics of both pyrene and perylene units. The cationic surfactant cetyltrimethylammonium bromide (CTAB) can efficiently regulate the fluorescence emission of PEPBI from pyrene monomer to pyrene monomer-perylene co-emission in aqueous solution. The selected fluorescent ensemble based on PEPBI/CTAB assembly showed ratiometric responses to nonmetalloproteins and turn-off responses to metalloproteins. Collecting the data of fluorescence variation of both pyrene and perylene units at six wavelengths can form specific recognition fingerprints for both nonmetalloproteins and metalloproteins. Using linear discriminant analysis, the sensor ensemble can discriminate four nonmetalloproteins and four metalloproteins. In this work, the combination of surfactant assemblies’ modulation effect and a dual-fluorophore with multiple emission bands realizes the discrimination of same type of proteins by a single sensor system.