Highly sensitive upconversion fluorescence detection for glutathione by lanthanide-doped nanoparticles encapsulated with MnO2

Abstract

To improve the quantitative detection sensitivity of glutathione (GSH) by upconversion fluorescence, composites of lanthanide-doped upconversion nanoparticles (UCNPs) with tightly encapsulated manganese dioxide (MnO2) energy acceptor have been designed and prepared. Compared to the assemblies of MnO2 nanosheets embedded UCNPs, MnO2 in close-packed structures acts as a more effective and efficient bursting agent for UCNPs to seal them properly in their luminescence off state. With the presence of GSH, MnO2 is reduced to Mn2+ and this process provides an opportunity for fluorescence intensity of UCNPs to be significantly recovered and become more pronounced with the contribution of both internal filtration effects and fluorescence resonance energy transfer mechanisms. Under the optimized conditions, the quantitative sensing of GSH is achieved in the detection range from 0.40 μM to 116.00 μM, with the limit of detection of 31.2 nM and good selectivity.