A porphyrin-based near-infrared fluorescent sensor for sulfur ion detection and its application in living cells

Sulfide anion (S2-) has been known as toxic species for many years. Notably, hydrogen sulfide (H2 S), as its protonated product, is recently recognized as the third endogenous gaseous transmitter and is related to many diseases. Thus, it is of vital importance to achieve rapid, sensitive and selective detection of S-2- in various conditions. Herein, we firstly report a novel porphyrin-based NIR turn-on fluorescent sensor for S2- detection. The pristine sensor displays weak fluorescence due to the photo-induced electron transfer (PET) process which occurs from porphyrin fluorophore to the electron-withdrawing 2,4-dinitrobenzenesulfonyl group. Upon being with S2-, the 2,4-dinitrobenzenesulfonyl group of the sensor is efficiently removed and the significant NIR fluorescence enhancement can be observed. Exhibiting a large NIR fluorescence turn-on signal, the sensor shows high sensitivity, high selectivity as well as quick response (similar to 60 s) when detecting 52-. Moreover, it displays very low cytotoxicity and can be employed to monitor S2- levels in tap water and living cells. Overall, this simple strategy may be used for development of NIR fluorescent sensors towards a wide variety of analytes. (C) 2016 Elsevier B.V. All rights reserved.