title: Accurate Quantitative Sensing of Intracellular pH based on Self-ratiometric Upconversion Luminescent Nanoprobe.
abstract: Accurate quantitation of intracellular pH (pHi) is of great importance in revealing the cellular activities and early warning of diseases. A series of fluorescence-based nano-bioprobes composed of different nanoparticles or/and dye pairs have already been developed for pHisensing. Till now, biological auto-fluorescence background upon UV-Vis excitation and severe photo-bleaching of dyes are the two main factors impeding the accurate quantitative detection of pHi. Herein, we have developed a self-ratiometric luminescence nanoprobe based on förster resonant energy transfer (FRET) for probing pHi, in which pH-sensitive fluorescein isothiocyanate (FITC) and upconversion nanoparticles (UCNPs) were served as energy acceptor and donor, respectively. Under 980 nm excitation, upconversion emission bands at 475 nm and 645 nm of NaYF4:Yb3+, Tm3+UCNPs were used as pHiresponse and self-ratiometric reference signal, respectively. This direct quantitative sensing approach has circumvented the traditional software-based subsequent processing of images which may lead to relatively large uncertainty of the results. Due to efficient FRET and fluorescence background free, a highly-sensitive and accurate sensing has been achieved, featured by 3.56 per unit change in pHivalue 3.0-7.0 with deviation less than 0.43. This approach shall facilitate the researches in pHirelated areas and development of the intracellular drug delivery systems.
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.|Graduate University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Cuixia
authors.initials: C
authors.lastname: Li
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.|Graduate University of the Chinese Academy of Sciences, Beijing 100049, China.|Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Jing
authors.initials: J
authors.lastname: Zuo
authors.affiliation: Department of Basic Medicine, Gerontology Department of First Bethune Hospital, University of Jilin, Changchun 130021, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
authors.forename: Yulei
authors.initials: Y
authors.lastname: Chang
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
authors.forename: Youlin
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.|Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Langping
authors.initials: L
authors.lastname: Tu
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.|Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Bin
authors.initials: B
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.|Graduate University of the Chinese Academy of Sciences, Beijing 100049, China.|Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Qiqing
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Basic Medicine, Gerontology Department of First Bethune Hospital, University of Jilin, Changchun 130021, China.
authors.forename: Huiying
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
authors.forename: Xianggui
authors.initials: X
authors.lastname: Kong
mesh_terms: D015374:Biosensing Techniques; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D006863:Hydrogen-Ion Concentration; D042541:Intracellular Space; D049408:Luminescent Agents; D057054:Molecular Imaging; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D015018:Ytterbium / Q000737:chemistry
chemical_list: D049408:Luminescent Agents; D015018:Ytterbium