A near-infrared ratiometric fluorescent probe for rapid and highly sensitive imaging of endogenous hydrogen sulfide in living cells

Abstract

We describe the design and synthesis of a cyanine-based near-infrared ratiometric fluorescent probe, HS-Cy, for H 2 S detection, which features rapid response, high sensitivity, and mitochondria targeting. After a rapid quenching at 780 nm by initial nucleophilic addition on the aldehyde group, HS-Cy experienced a polymethine p-electron conjugation modulation triggered by a second nucleophilic addition on the ester, releasing the cyanine fluorophore which underwent tautomerism from enol form to ketone form. Therefore, gradual emergence of a new peak at 625 nm was observed, constructing a ratiometric signal for H 2 S with a detection limit of 5.0-10 nM, which is the most sensitive among the reported H 2 Ssensing fluorescent probes. HS-Cy was proven to selectively locate into mitochondria with faster trapping kinetics towards H 2 S. Based on this, the endogenously generated H 2 S in human A549 cells was ratiometrically detected and imaged by HS-Cy.

In situ quantification and evaluation of ClO−/H2S homeostasis in inflammatory gastric tissue by applying a rationally designed dual-response fluorescence probe featuring a novel H+-activated mechanism

“…1, the linear relationships with the quite low detection limits of 2.7 nM and 6.9 nM were achieved respectively for ClO -and H 2 S. Undoubtedly, the detection limit for H 2 S with BNBD was comparable to the detection limit provided by the chemical probe reported as the most sensitive 34 , so was the detection limits for ClO -46 . We attribute the high detection sensitivity to both the large (150 fold) Off-On-Off switch of fluorescence and the strong oxidizing power of nitro group and ClO -under the acidic condition.…”

“…On the other hand, in situ determination of endogenous H 2 S in tissue is still a challenge, because it requires the rapid and sensitive response. It was found that sensing H 2 S through the nucleophilic attack or CuS precipitation needed relatively long time 34 . Though azide in fluorophore could rapidly report the trace level of H 2 S within minutes, it might be protonated in the highly acidic environment.…”

A Copper Porphyrin for Sensing H2S in Aqueous Solution via a “Coordinative‐Based” Approach

“…Recently, fluorescence-based systems for H 2 S detection have been proposed as selective probes for biological applications. [9][10][11][12][13][14][15][16][17][18][19][20] These probes can detect H 2 S in aqueous solution with high sensitivity and selectivity. Existing fluorescencebased probes implemented so far have been subdivided into four different categories (depending on the reaction mechanism by which analyte recognition occurs): [1,19] (i) azide-toamine reduction; [12,[21][22][23][24][25][26][27] (ii) nucleophilic addition; [28][29][30][31] (iii) copper displacement; [32][33][34][35][36] and (iv) nitro-to-amine reduction.…”

FRET ratiometric probes reveal the chiral-sensitive cysteine-dependent H2S production and regulation in living cells

“…2) the interruption of a large conjugate system by H 2 S addition can produce ratiometric probes with relatively large Stokes shifts. However, this method can only turn-on the signal at the shorter emission wavelength [25][26][27] . If we employ FRET effect as an alternative strategy for ratiometric H 2 S probes, 1) the turn-on signal can be at longer emission wavelength (FRET acceptor emission) and 2) the FRET pairs could be chosen flexibly for facile control of two emission wavelengths at specific wavelength ranges.…”

“…The intensity-based fluorescence probes may suffer from multiple factors to influence the accurate analysis of H 2 S production and regulation in living cells. However, the ratiometric fluorescence probes provide built-in correction for environmental effects to improve the accuracy of bioimaging analysis [22][23][24][25][26][27] . The reported sulfide ratiometric probes are mainly based on two strategies: 1) a tuneable electronic system, after reaction with H 2 S, results in a spectroscopic alteration such as blue or red shift in emission.…”