A two-photon fluorescent probe for specific detection of hydrogen sulfide based on a familiar ESIPT fluorophore bearing AIE characteristics

Abstract

Hydrogen sulfide (HS) is a signaling gasotransmitter, which plays various roles in modulating the functions of different systems. In this study, a "turn-on" fluorescent probe for HS was developed. The probe, whose design is based on a familiar excited state intramolecular proton transfer (ESIPT) fluorophore bearing aggregation-induced emission (AIE) characteristics, was found to exhibit an 80-fold fluorescence enhancement along with a large Stokes shift upon the addition of HS. Furthermore, the probe was successfully utilized to detect HS in HeLa cells with both one-photon and two-photon microscopy.

In Situ Localization of Enzyme Activity in Live Cells by a Molecular Probe Releasing a Precipitating Fluorochrome

“…The large Stokes shift of HTPQ contributes additional and highly desirable advantages: increased sensitivity, minimized background fluorescence, and enhanced bioimaging contrast. Importantly, its essential properties of insolubility and intense fluorescence can be countered, yes reversed, by denying it the establishment of an internal hydrogen bond between the phenolic hydroxy group and the imine nitrogen . We further utilized HTPQ in the design of an enzyme‐responsive, fluorogenic probe (HTPQA), targeting alkaline phosphatase (ALP) as a model enzyme (Scheme ).…”

“…[6] Unfortunately,i ts maximum excitation wavelength of 350 nm is not particularly well adapted to fluorescence imaging with confocal microscopes,because the latters shortest excitation wavelength is at 405 nm. [7,8] We further utilized HTPQ in the design of an enzyme-responsive,f luorogenic probe (HTPQA), targeting alkaline phosphatase (ALP) as am odel enzyme (Scheme 1). HTPQ is found to be strictly insoluble in water, and shows intense fluorescence in the solid state with maximum excitation and emission wavelengths at 410 nm and 550 nm, respectively.T his makes it far better suited to the use with aconfocal microscope.The large Stokes shift of HTPQ contributes additional and highly desirable advantages:i ncreased sensitivity,m inimized background fluorescence,and enhanced bioimaging contrast.…”

Fluorescent AIE-Active Materials for Two-Photon Bioimaging Applications

“…As a signal gas transmitter, H 2 S plays a vital role in regulating the different functions of life systems (Hong et al, 2018;Wang J. et al, 2020;Zhang D. et al, 2020). Yoon's group developed a two-photon AIE probe 1 based on the mechanism of excited-state intramolecular proton transfer (ESIPT) for fluorescent turn-on detection of H 2 S (Figure 2A) (Chen et al, 2017). The probe 1 showed almost no fluorescence due to free motion and inhibited ESIPT effect.…”

A review: Red/near‐infrared (NIR) fluorescent probes based on nucleophilic reactions of H2S since 2015

“…In recent years, various fluorescent probes have been developed for specifically monitoring H 2 S in vitro and in vivo , using three main response strategies: (i) H 2 S reductive reactions [ 45–54 ] ; (ii) H 2 S nucleophilic reactions [ 55–64 ] ; (iii) copper sulfide precipitation reaction. [ 65–67 ] The biological system is quite a complicated environment, in which interference by other sulfur‐containing substances may exist during H 2 S detection.…”