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.