Ruthenium(II) and Nitro Co-Functionalized UiO-66 for Smartphone-Integrated Visual Detection and Cellular Imaging of H2S

Hydrogen sulfide (H2S) is an environmental toxin originating from the sulfur industry as well as an important gasotransmitter that regulates physiological and pathological processes. Therefore, accurate and portable on-site monitoring H2S is imperative for ensuring environmental safety as well as understanding its physiological and pathological functions. Herein, a new colorimetric and ratiometric fluorescence dual-mode sensor has been constructed for visual detection of H2S by encapsulating [Ru(bpy)3]2+ into a nitro-functionalized Zr-based organic framework (Ru@UiO-66-NO2). The accommodated [Ru(bpy)3]2+ not only offers a reference fluorescence but also provides catalytic active sites to decompose H2O2 into •OH that oxidizes substrate o-phenylenediamine (OPD), whereas the nitro groups in the skeleton serves as reactive sites for H2S. When H2S is present, the blue emission of Ru@UiO-66-NO2 at 433 nm boosts greatly because it can reduce nitro to amine, while the red one at 623 nm originated from [Ru(bpy)3]2+ stays unchanged. Meanwhile, H2S eliminates the generated •OH, decreases the OPD oxidation, and finally lightens the yellow color. Additionally, a smartphone-integrated sensor with colorimetric and ratiometric fluorescence dual signals has been developed for portable and visual detection of H2S. This system can be extended to H2S detection in environmental water samples and imaging in HeLa cells, revealing its considerable potential for more extensive practical scenarios.