title: Reversible off-on fluorescence probe for hypoxia and imaging of hypoxia-normoxia cycles in live cells.
abstract: We report a fully reversible off-on fluorescence probe for hypoxia. The design employs QSY-21 as a Förster resonance energy transfer (FRET) acceptor and cyanine dye Cy5 as a FRET donor, based on our finding that QSY-21 undergoes one-electron bioreduction to the radical under hypoxia, with an absorbance decrease at 660 nm. At that point, FRET can no longer occur, and the dye becomes strongly fluorescent. Upon recovery of normoxia, the radical is immediately reoxidized to QSY-21, with loss of fluorescence due to restoration of FRET. We show that this probe, RHyCy5, can monitor repeated hypoxia-normoxia cycles in live cells.
authors.affiliation: Faculty of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Shodai
authors.initials: S
authors.lastname: Takahashi
authors.forename: Wen
authors.initials: W
authors.lastname: Piao
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Matsumura
authors.forename: Toru
authors.initials: T
authors.lastname: Komatsu
authors.forename: Tasuku
authors.initials: T
authors.lastname: Ueno
authors.forename: Takuya
authors.initials: T
authors.lastname: Terai
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kamachi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kohno
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nagano
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Hanaoka
mesh_terms: D000880:Anthraquinones / Q000737:chemistry; D045744:Cell Line, Tumor; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D000860:Hypoxia; D018613:Microscopy, Confocal; D015394:Molecular Structure; D009711:Nucleotides / Q000737:chemistry; D010084:Oxidation-Reduction; D012235:Rhodamines / Q000737:chemistry; D012394:Rosaniline Dyes / Q000737:chemistry
chemical_list: D000880:Anthraquinones; D005456:Fluorescent Dyes; D009711:Nucleotides; C554276:QSY 21 compound; D012235:Rhodamines; D012394:Rosaniline Dyes; C005095:malachite green; C022970:2-aminoanthraquinone