Development of Fluorescent Reagent Based on Ligand Exchange Reaction for the Highly Sensitive and Selective Detection of Dopamine in the Serum

A new fluorescent probe (BDP-Fe(2+)) was developed for targeting dopamine, with a boron–dipyrromethenyl (BDP) group as the fluorophore and a Fe(2+) complex as the ligand exchange site. The free form of BDP-Fe(2+) in solution displayed weak fluorescence emission, while it showed strong fluorescence emission after interaction with dopamine due to the release of Fe(2+) from BDP-Fe(2+), confirming the binding of Fe(2+) to dopamine. The increase in fluorescence intensity was concentration-dependent, and a good linear relationship was observed between the fluorescence intensity and dopamine concentration. The detection limit of dopamine by BDP-Fe(2+) was 1.1 nM, indicating a 20-fold higher sensitivity than that of previously reported compounds. The reaction of BDP-Fe(2+) with dopamine was not affected by the presence of foreign substances, allowing the highly selective detection of dopamine in the human serum sample. The results of this study indicate that the novel compound BDP-Fe(2+) is a reliable fluorescent molecular probe for the detection of dopamine and can be widely employed in diverse scientific areas.