title: Upconversion nanoparticle-based fluorescence resonance energy transfer assay for Cr(III) ions in urine.
abstract: A novel assay of chromium(III) ion based on upconversion fluorescence resonance energy transfer was designed and established. Lysine-capped NaYF(4):Yb/Er upconversion nanoparticles (UCNPs) and dimercaptosuccinic acid-capped gold nanoparticles (AuNPs) were used as the energy donor and acceptor, respectively. They were bound together via electrostatic interaction, resulting in the quenching of the fluorescence of UCNPs by AuNPs. Chromium(III) ions can specifically and strongly interact with dimercaptosuccinic acid that was modified on the surface of AuNPs, leading to the separation of AuNPs from UCNPs and the recovery of fluorescence of UCNPs. The fluorescence recovery of UCNPs showed a good linear response to Cr(3+) concentration in the range of 2-500 nM with a detection limit of 0.8 nM. This method was further applied to determine the levels of Cr(3+) in urine. Compared with other fluorescence methods, current method displayed very high sensitivity and signal-to-noise ratio because of the excitation of near-infrared that can eliminate autofluorescence, providing a promising examination of biological samples for the diagnostic purposes.
authors: State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, PR China.
authors: Baoxia
authors: B
authors: Liu
authors: Hongliang
authors: H
authors: Tan
authors: Yang
authors: Y
authors: Chen
mesh_terms: D002412:Cations / Q000652:urine*; D002857:Chromium / Q000652:urine*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D008239:Lysine / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D059629:Signal-To-Noise Ratio; D004113:Succimer / Q000737:chemistry
chemical_list: D002412:Cations; D002857:Chromium; D006046:Gold; D004113:Succimer; D008239:Lysine