An activatable ratiometric near-infrared fluorescent probe for hydrogen sulfide imaging in vivo (original) (raw)

2020, Science China Chemistry

Ratiometric fluorescent probes hold great promise for in vivo imaging; however, stimuli-activatable ratiometric probes with fluorescence emissions in near-infrared (NIR) region are still very few. Herein, we report a hydrogen sulfide (H 2 S)-activatable ratiometric NIR fluorescent probe (1-SPN) by integrating a H 2 S-responsive NIR fluorescent probe 1 into a H 2 S-inert poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT)-based NIR semiconducting polymer nanoparticle (SPN). 1-SPN shows "always on" PCPDTBT fluorescence at 830 nm and weak probe 1 fluorescence at 725 nm under excitation at 680 nm. The ratio of NIR fluorescence intensities between 725 and 830 nm (I 725 /I 830) is small. Upon interaction with H 2 S, the fluorescence at 725 nm is rapidly switched on, resulting in a large enhancement of I 725 / I 830 , which is allowed for sensitive visualization and quantification of H 2 S concentrations in living cells. Taking advantage of enhanced tissue penetration depth of NIR fluorescence, 1-SPN is also applied for real-time ratiometric fluorescence imaging of hepatic and tumor H 2 S in living mice. This study demonstrates that activatable ratiometric NIR fluorescent probes hold great potential for in vivo imaging. ratiometric probe, activatable probe, near-infrared fluorescence, molecular imaging, H 2 S