A new kind of rhodamine-based fluorescence turn-on probe for monitoring ATP in mitochondria

We have developed a new kind of colorimetric and fluorescence turn-on probe based on rhodamine derivatives for the detection of adenosine-5'-triphosphate (ATP) through hydrogen bond interactions. Upon the addition of 5mM ATP, the probe 1 shows a 65-fold enhancement in fluorescence intensity and a color change from colorless to pink. The probe 2 also shows very obvious color and fluorescence change with the presence of ATP. The experimental results show that this kind of probe has high specificity towards ATP over other anions, metal ions, and other nucleoside polyphosphates, except ADP. The enhanced emission and naked eye changes are attributed to spirolactam ring-opening, which is pH independent (pH (4.0-7.4)). The more important finding from our results is that the electron withdrawing group in the chain decreases the binding ability to ATP. The live cell imaging experiments in Hela cells indicated that probe 2 has cell permeability, and mainly locates to mitochondria. (C) 2018 Elsevier B.V. All rights reserved.