title: Construction of LRET-based nanoprobe using upconversion nanoparticles with confined emitters and bared surface as luminophore.
abstract: Upconversion nanoparticles (UCNPs) are promising energy donors for luminescence resonance energy transfer (LRET) and have widely been used to construct nanoprobes. To improve the LRET efficiency, which is currently a limiting factor for UCNPs-based bioassay, we herein propose a strategy to construct LRET-based nanoprobe using UCNPs with confined emitters and bared surface as the luminophore, with Ca(2+) as the proof-of-concept target. The sandwich-structure upconversion nanoparticles (SWUCNPs) are designed with a core-inner shell-outer shell architecture, in which the emitting ions (Ln(3+)) are precisely located in the inner shell near the particle surface, which is close enough to external energy acceptors. The target receptor (Fluo-4) is directly tagged on bared surface of SWUCNPs, which further reduces the donor-to-acceptor distance. Our strategy contributes to significantly improved LRET efficiency and hence affords an ultrahigh sensitivity for Ca(2+) detection. The as-constructed nanoprobe is structurally stable and exhibits good biocompatibility, which ensures uptake and reliable observation in living cells. The nanoprobe can be used for monitoring the different levels of cytosol [Ca(2+)] in living cells. Furthermore, it is applicable in Ca(2+) imaging in mice liver tissues.
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University , Wuhan 430072, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Songwei
authors.initials: S
authors.lastname: Lv
authors.forename: Yali
authors.initials: Y
authors.lastname: Wang
authors.forename: Shiyu
authors.initials: S
authors.lastname: Chen
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D000818:Animals; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D006367:HeLa Cells / Q000187:drug effects; D006801:Humans; D008099:Liver / Q000378:metabolism; D051379:Mice; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry / Q000633:toxicity; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D014961:X-Ray Diffraction; D014966:Xanthenes / Q000737:chemistry; D015018:Ytterbium / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; C409648:Fluo 4; D014966:Xanthenes; D015018:Ytterbium; D002118:Calcium