The ATP indicator system. Adenosine 5′-triphosphate (ATP) is a multifunctional molecule that participates in many important biological processes. Currently, fluorescence indicators for ATP with high performance are in demand. Reported herein is a novel water-soluble triarylboron compound which displays an apparent ATP-dependent fluorescence enhancement when dispersed in water. It can selectively recognize ATP from other bioactive substances in vitro and in vivo. The ATP-induced finite aggregation endows the indicator with appreciable photostability and superior tolerance to environmental electrolytes. This indicator has been successfully applied to the ATP imaging in NIH/3T3 fibroblast cells. The difference in the ATP levels within the membrane and cytosol is clearly visible. Angewandte Chemie, 2014 a) UV absorption and b) fluorescence spectral changes of DPTB-IMI-EG (10 μm) upon addition of the sodium salt of ATP (1–5000 μm). c) Photograph of DPTB-IMI-EG in the presence and absence of ATP (1 mm). d) Fluorescence titration curve of DPTB-IMI-EG upon the addition of AMP (blue), ADP (red), and ATP (black). I/I0 means the fluorescence intensity (λ=510 nm) changes and I0 is the initial fluorescence intensity (λ=510 nm) of DPTB-IMI-EG in the absence of nucleotides. Conditions: λex=440 nm, [DPTB-IMI-EG]=10 μm, pH 7.4 (10 mm HEPES), 37 °C. Confocal fluorescence images of live NIH/3T3 cells incubated with (A2–D2) or without (A1–D1) apyrase (1 U mL−1) in DMEM for 60 min at 37 °C and then incubated with DPTB-IMI-EG and MDRF. A) Green channel for DPTB-IMI-EG (1 μm). B) Red channel for MDRF (100 nm). C) Panels A and B merged. D) Optical image. Confocal fluorescence images of live NIH/3T3 cells stained with DPTB-IMI-EG (1 μm) for 30 min in DMEM. a) Fluorescence intensity image. b) Merged intensity and lifetime image. Excitation wavelength: λ=405 nm. Emission wavelength: λ=460–550 nm. |
