Responsive β-Diketonate-europium(III) Complex-Based Probe for Time-Gated Luminescence Detection and Imaging of Hydrogen Sulfide In Vitro and In Vivo .

As a crucial biological gasotransmitter, hydrogen sulfide (H 2 S) plays important roles in many pathological and physiological processes. Highly selective and sensitive detection of H 2 S is significant for the precise diagnosis and evaluation of diverse diseases. Nevertheless, challenges remain in view of the interference of autofluorescence in organisms and the stronger reactivity of H 2 S itself. Herein, we report the design and synthesis of a novel H 2 S-responsive β-diketonate-europium(III) complex-based probe, [Eu(DNB-Npketo) 3 (terpy)], for background-free time-gated luminescence (TGL) detection and imaging of H 2 S in autofluorescence-rich biological samples. The probe, consisting of a 2,4-dinitrobenzenesulfonyl (DNB) group coupled to a β-diketonate-europium(III) complex, shows almost no luminescence owing to the existence of intramolecular photoinduced electron transfer. The cleavage of the DNB group by a H 2 S-triggered reaction results in the recovery of the long-lived luminescence of the Eu 3+ complex, allowing the detection of H 2 S in complicated biological samples to be performed in TGL mode. The probe showed a fast response, high specificity, and high sensitivity toward H 2 S, which enabled it to be successfully used for the quantitative TGL detection of H 2 S in tissue homogenates of mouse organs. Additionally, the low cytotoxicity of the probe allowed it to be further used for the TGL imaging of H 2 S in living cells and mice under different stimuli. All of the results suggested the potential of the probe for the investigation and diagnosis of H 2 S-related diseases.