A unique turn-off fluorescent strategy for sensing dopamine based on formed polydopamine (pDA) using graphene quantum dots (GQDs) as fluorescent probe

A rapid, facile fluorescence sensing strategy was developed for dopamine (DA) detection based on polydopamine (pDA) formed on the surface of graphene quantum dots (GQDs). The prepared GQDs were strongly luminescent because of the aromatic planar structure. DA could self-polymerize to pDA and snap to the surface of GQDs to form a thin film in alkaline environment, leading to quenching of fluorescence due to fluorescence resonance energy transfer (FRET). With the optimized conditions, the analytical performance illustrated high sensitivity, selectivity in a wide linear range with a detection limit of 8 nM. In addition, the unique method was successfully applied for DA injection test with satisfactory labeled amount. Finally, the proposed strategy was applied for DA detection in serum, wherein accurate results were obtained.