Lanthanide metal-organic frameworks based smart labels for accurate temperature monitoring

Lanthanide metal-organic frameworks (Ln-MOFs) have temperature-responsive luminescent properties for sensing applications. In this study, we developed a dual-emission fluorescent label (SCF-TGIC@MOF) with temperature-responsive properties, achieved by doping epoxy-modified Eu-MOF (TGIC@Eu-MOF) into a sodium alginate/carboxymethylcellulose composite substrate containing fluorescein (SCF). The composites modified with triglycidyl isocyanurate (TGIC) showed improved fluorescence intensity, thermal stability, and relative sensitivity compared with unmodified Eu-MOF. The composite of the substrate improved the physicochemical stability of the label, while the label showed a visible green to red fluorescence transition corresponding to temperature changes in the physiological range (277.15-313.15 K). The responsiveness of the label to temperature suggests that it has the potential to be used as a luminescent thermometer. In addition, the monitored temperature range suggests that the smart label has value for applications in environmental temperature monitoring. And this may apply to the preservation and storage of food products, such as vegetables and aquatic products.