Near-IR discriminative detection of H2S and Cysteine with 7-nitro-2,1,3-benzoxadiazole-perylenediimide conjugate in water, live cells and solid state: Mimicking IMP, INH and NOR/OR complimentary logic

Abstract

Design of ratiometric probes which can differentiate bioactive sulphur species (H2S, Cys and GSH) are in demand. In this work, perylenediimide–7-nitro-2,1,3-benzoxadiazole based near-IR chromofluorescent probe (NBD-PDI) was designed for discriminative detection of H2S and Cysteine. The chemodosimetric reaction of NBD-PDI with H2S induces cleavage of the NBD moiety via thiolysis and thereby affords PDI-OH (λmax 680 nm) and NBD-SH (λmax 550 nm) with diminution of emission intensity at 537 nm. Meanwhile after the reaction of NBD-PDI with cysteine, only absorbance at 680 nm observed while emission at 660 nm decreased and 537 nm increased. The intensities of NBD-PDI showed linearity with increase of H2S and Cys concentrations with detection limits of 3.29 μM and 13.5 μM (UV–vis); 1.3 μM and 3 μM (fluorescence), respectively. Moreover, applicability of NBD-PDI for the fluorescence imaging of H2S and cysteine in MG-63 cells was investigated. The unique differential response of NBD-PDI towards H2S and Cysteine allowed fabrication of IMP, INH, OR, NOR and TRANSFER logic gates. NBD-PDI coated TLC strips can be used for visualization of H2S/Cysteine and for writing alphabets using H2S/Cysteine as ink. The mechanism of H2S interaction using 1H NMR titration, DFT and CV studies are also discussed.