Ag island film-enhanced rare earth co-luminescence effect of Tb–Gd–protein–sodium dodecyl benzene sulfonate system and sensitive detection of protein

This paper reported the coupling technique of Ag island film-enhanced fluorescence with rare earth co-luminescence effect of Tb–Gd–sodium dodecyl benzene sulfonate (SDBS)–protein system. While the collagen is used as the separator between Ag island film and the fluorophore because it not only can decrease the fluorescence of the blank, but also can promote the adsorption of other proteins and change the conformation of the protein. The effects of Ag island film on both the fluorescence and resonance energy transfer process of Tb–Gd–SDBS–protein system are studied, finding that Ag island film can enhance the energy transfer efficiency of this system, resulting in fluorescence enhancement about tenfold compared with this system without Ag island film. Therefore, this technique is used for the detection of proteins as low as 0.72 ng/mL for BSA and 1.3 ng/mL for HSA. In addition, Ag island film can also change the energy transfer process of Tb–SDBS–protein system.