A highly sensitive and specific luminescent MOF determines nitric oxide production and quantifies hydrogen sulfide-mediated inhibition of nitric oxide in living cells.

The synthesis of a novel carboxylate-type organic linker-based luminescent MOF (Zn(H 2 L) (L 1 )) (named PUC2) (H 2 L = 2-aminoterephtalic acid, L 1  = 1-(3-aminopropyl) imidazole) is reported by the solvothermal method and comprehensively characterized using single-crystal XRD, PXRD, FTIR, TGA, XPS, FESEM, HRTEM, and BET. PUC2 selectively reacts with nitric oxide ( ▪ NO) with a detection limit of 0.08 µM, and a quenching constant (0.5 × 10 4  M -1 ) indicating a strong interaction with ▪ NO. PUC2 sensitivity remains unaffected by cellular proteins or biologically relevant metals (Cu 2+ / Fe 3+ /Mg 2+ / Na + /K + /Zn 2+ ), RNS/ROS, or H 2 S to score ▪ NO in living cells. Lastly, we used PUC2 to demonstrate that H 2 S inhibition increases ▪ NO production by ~ 14-30% in various living cells while exogenous H 2 S suppresses ▪ NO production, indicating that the modulation of cellular ▪ NO production by H 2 S is rather generic and not restricted to a particular cell type. In conclusion, PUC2 can successfully detect ▪ NO production in living cells and environmental samples with considerable potential for its application in improving the understanding of the role of ▪ NO in biological samples and study the inter-relationship between ▪ NO and H 2 S.