title: Through bond energy transfer: a convenient and universal strategy toward efficient ratiometric fluorescent probe for bioimaging applications.
abstract: Fluorescence resonance energy transfer (FRET) strategy has been widely applied in designing ratiometric probes for bioimaging applications. Unfortunately, for FRET systems, sufficiently large spectral overlap is necessary between the donor emission and the acceptor absorption, which would limit the resolution of double-channel images. The through-bond energy transfer (TBET) system does not need spectral overlap between donor and acceptor and could afford large wavelength difference between the two emissions with improved imaging resolution and higher energy transfer efficiency than that of the classical FRET system. It seems to be more favorable for designing ratiometric probes for bioimaging applications. In this paper, we have designed and synthesized a coumarin-rhodamine (CR) TBET system and demonstrated that TBET is a convenient strategy to design an efficient ratiometric fluorescent bioimaging probe for metal ions. Such TBET strategy is also universal, since no spectral overlap between the donor and the acceptor is necessary, and many more dye pairs than that of FRET could be chosen for probe design. As a proof-of-concept, Hg(2+) was chosen as a model metal ion. By combining TBET strategy with dual-switch design, the proposed sensing platform shows two well-separated emission peaks with a wavelength difference of 110 nm, high energy transfer efficiency, and a large signal-to-background ratio, which affords a high sensitivity for the probe with a detection limit of 7 nM for Hg(2+). Moreover, by employing an Hg(2+)-promoted desulfurization reaction as recognition unit, the probe also shows a high selectivity to Hg(2+). All these unique features make it particularly favorable for ratiometric Hg(2+) sensing and bioimaging applications. It has been preliminarily used for a ratiometric image of Hg(2+) in living cells and practical detection of Hg(2+) in river water samples with satisfying results.
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082.
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Gong
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Zhang
authors.forename: Cui-Cui
authors.initials: CC
authors.lastname: Zhang
authors.forename: Ai-Li
authors.initials: AL
authors.lastname: Luo
authors.forename: Ting
authors.initials: T
authors.lastname: Fu
authors.forename: Weihong
authors.initials: W
authors.lastname: Tan
authors.forename: Guo-Li
authors.initials: GL
authors.lastname: Shen
authors.forename: Ru-Qin
authors.initials: RQ
authors.lastname: Yu
mesh_terms: D004735:Energy Transfer / Q000502:physiology; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D061848:Optical Imaging / Q000379:methods
chemical_list: D005456:Fluorescent Dyes