A multi-ratiometric fluorescence sensor integrated intrinsic signal amplification strategy for a sensitive and visual assay of the anthrax biomarker based on a bimetallic lanthanide metal–organic framework. Issue 2 (24th January 2023) - Han, Lei
Abstract : A multi-ratiometric fluorescence sensor was designed for the sensing of the anthrax biomarker based on a bimetallic lanthanide metal–organic framework. Abstract : The development of sensitive and prompt approaches for reliable determination of dipicolinic acid (DPA) is of great importance for human health and public security. Herein, we synthesized a bimetallic lanthanide metal–organic framework (Tb/Eu-MOF) using 2-hydroxyterephthalic acid as a ligand and lanthanide ions (Tb 3+ and Eu 3+ ) as central metal ions. The as-synthesized Tb/Eu-MOF possesses multiple recognition sites toward DPA. When present, DPA can displace the chelated water molecules and then coordinate with Tb 3+ and Eu 3+ to sensitize their luminescence. This causes the fluorescence of Tb 3+ (546 nm) and Eu 3+ (617 nm) to increase, while that of the ligand (432 nm) remains constant. Based on the multiple fluorescence signal responses of Tb/Eu-MOF toward DPA, a multi-ratiometric fluorescence sensor using ( F 546 / F 432 ) and ( F 617 / F 432 ) as output signals was developed to detect DPA. Moreover, an intrinsic signal amplification strategy is used to achieve more sensitive sensing of DPA by integrating the fluorescence signals of Tb 3+, Eu 3+, and ligand with ( F 546 + F 617 )/ F 432 as the output signal. Benefitting from the signal amplification and multiple fluorescence responses, this method shows high sensitivity and obvious fluorescence color variation toward DPA detection. This strategy offers a prompt, sensitive, and reliable method for the visual sensing of DPA.