Enhanced Ligand-Based Luminescence in Metal–Organic Framework Sensor

Metal–organic frameworks are appealing hybrid solids which attract continuously growing interest. Their advantageous application in sensing devices is demonstrated here. In particular, the use of a short-pulse laser excitation of luminescent metal-organic framework is reported for the first time to favor the ligand-based emission. The designed MOF-based system achieves in vitro H2S dosing by turn-on fluorescence with unprecedented sensitivity. The Al-MIL-101-based sensor detects sulfide produced by living cells and sulfide-releasing molecules in physiological media with a constant accuracy at sub-micromolar levels. The reported sensitivity is suitable for medical applications and opens new perspectives in the design of new point-of-care testing devices. The detailed relationship between photoluminescence mechanisms and chemical modification of the MOF upon sensing is also reported.