Luminescence resonance energy transfer probes based on NaYF4:Yb, Er-Ag nanocompounds for sensitive detection of Mn2+ ions

In this paper, a novel detection method based on luminescence resonance energy transfer (LRET) system for sensitive detection of Mn 2+ ions has been proposed. The positively charged upconversion nanoparticles capped with polyethyleneimin (PEI-UCNPs) and negatively charged Ag NPs capped with tripolyphosphate (P 3 O 10 5− -Ag NPs) were bound through electrostatic interaction . They were used as energy donors and acceptors, respectively. The green upconversion luminescence could be quenched because of a good overlap between the UCNPs emission and the Ag NPs absorption spectra . Nevertheless, the LRET was disrupted and the green upconversion luminescence was restored in the presence of Mn 2+ because of the coagulation of P 3 O 10 5− -Ag NPs. Thus, the relative luminescence intensity increased as the concentrations of Mn 2+ increased. The response is linear to the concentrations of Mn 2+ in the range from 0.2 to 5 μM, and the detection limit is evaluated to be 150 nM (S/N = 3). This probe was easy to operate with satisfactory selectivity and excellent sensitivity, which would be able to satisfy the requirements of Mn 2+ -related detection.