Upconversion luminescence nanoprobe based on luminescence resonance energy transfer from NaYF4:Yb, Tm to Ag nanodisks
In this work, we reported a luminescence probe based on luminescence resonance energy transfer (LRET), in which the positively charged upconversion nanoparticles (UCNPs) were used as the energy donors and the negatively charged Ag nanodisks (Ag NPs) as the energy acceptors. They bound together through electrostatic interaction, and luminescence quenching was observed due to the LRET from UCNPs to Ag NPs. However, the luminescence intensities recovered with the addition of cysteine (Cys). This was due to the formation of S–Ag bonds, which caused the inhibition of the LRET process. Under the optimized conditions, the relationship between the luminescence intensity and the concentration of cysteine were linear in the range from 50 to 2000 μM. The proposed LRET system also showed high selectivity to Cys and would also be used to detect other biothiols. Thus, the as-prepared probe possesses potential applications in the detection of biothiols.