Cu2Â + modulated BSA-Au nanoclusters: A versatile fluorescence turn-on sensor for dopamine

In this work, Cu2 + modified BSA stabilized gold nanoclusters (BSA-Au NCs) were fabricated for the fluorescence turn-on detection of dopamine, an important catecholamine neurotransmitter. The fluorescence of BSA-Au NCs was initially quenched by the Cu2 + ion, and then the addition of dopamine molecule causes the retrieval fluorescence by binding with the metal ion and removing it from the surface of BSA-Au NCs. The mode of interaction between metal ion with BSA-Au nanoclusters and dopamine was studied using fluorescence lifetime measurements, circular dichroism and infrared spectroscopy. The developed Cu2 + quenched BSA-Au nanocluster demonstrated high selectivity and sensitivity towards dopamine over other catecholamines and coexisting substances with a limit of detection 0.01 μM. The feasibility of the new turn on sensor in different real samples was demonstrated. The recovery of fluorescence by spiked analyte in human serum and urine samples ranged from 92 to 98% attesting the validity of the developed method.