Label-free detection of hemoglobin using GSH-AuAg NPs as fluorescent probe by dual quenching mechanism

In this work, a glutathione-induced AuAg nanoparticles (GSH-AuAg NPs) was simply prepared with good fluorescent performance attributed to aggregation induced emission (AIE). Then an accurate fluorescent analytical strategy for label-free detection of hemoglobin (Hb) is presented based on its quenching effect for this fluorescence. The effect of Ag doping in nanoparticle on its fluorescent property is discussed in details, thereafter the quenching effect composed of two different mechanisms as redox and inner filtering effect is proposed. To make full effects of the Hb for quenching the fluorescence, the conditions for material preparation and Hb detection are optimized. This method achieves wide quantitative range for Hb detection from 1 nM to 3.5 μM with a detection limit of 0.58 nM, and was applied in the determination of Hb concentration in real blood samples successfully.