Functionalized Metal–Organic Framework UiO-66-NH-BQB for Selective Detection of Hydrogen Sulfide and Cysteine

Hydrogen sulfide (H2S) is an important signaling molecule related to many diseases. Thus, H2S has a great impact on the pathological and physiological processes in biological systems. Cysteine (l-Cys) is a building block for proteins and important metabolites. To understand their roles in the physiological metabolic procedures, the measurement of the H2S level and identifying cysteine in the biological system is significant. In this study, through the functionalization of UiO-66-NH2 by 4-(2,2-dicyanoethenyl)benzoic acid (BQB), a novel UiO-66-NH-BQB is successfully synthesized and used as a fluorescence probe to recognize and detect H2S and l-Cys. The fluorescence signals of the probe are enhanced great when it is exposed to H2S or cysteine molecules; thus, it is able to determine quantificationally the H2S concentration in an aqueous solution. The detection limitation of the UiO-66-NH-BQB to H2S concentration is found to be as low as 1.74 μM. The developed fluorescent probe based on UiO-66-NH-BQB displays a high selectivity and excellent biocompatibility, which is very promising for recognition and sensing of biothiols in organisms.