Study on the co-luminescence effect of terbium-gadolinium-nucleic acids-cetylpyridine bromide system

In this paper, the luminescence mechanism of a new co-luminescence system (Tb-Gd-nucleic acids-cetylpyridine bromide) was studied. The experiment has shown that cetylpyridine bromide (CPB) could combine with nucleic acids through both electrostatic forces and hydrophobic forces, then Gd3+ and Tb3+ were bound to PO43- of nucleic acid and formed Tb-nucleic acid-CPB and Gd-nucleic acid-CPB complexes, respectively. When the system was excited, the DNA-CPB absorbed light energy and then transferred it to Tb3+ through both intramolecular energy transfer in Tb-nucleic acid-CPB complex and intermolecular energy transfer between Gd-nucleic acid-CPB and Tb-nucleic acid-CPB complexes. In addition, it was found that the gadolinium complex acted not only as the energy donor but also the energy-insulating sheath, which improved the fluorescence quantum efficiency