Synthesis of a lanthanide-based bimetallic-metal-organic framework for luminescence sensing anthrax biomarker

Lanthanide luminescence sensors have attracted extensive attention in the detection of 2, 6-pyridinedicarboxylic acid (DPA), the main biomarker of anthrax. In previous reports detecting DPA, luminescence probes may not have high selectivity and high specificity for identification. In the present study, a highly specific and sensitive luminescence probe was synthesized. In this paper, [TbxGd1-x (PBA)2NO3·2H2O]n is synthesized by solvothermal method using HPBA = 3.5-bis(triazol-1-yl)benzoic acid and Ln (NO3)3·6H2O (Ln = Tb, Gd). Through modulating the molar ratio of Tb3+ ions and Gd3+ ions, the distance between Ln3+ ions is changed, leading to a change in the energy transfer from the ligand to Tb3+, which in turn leads to an increase in luminescence intensity. Meanwhile the luminous colour is regulated by the ratio of Tb/Gd, which changes from green to white as the Gd ion gradually increases. The bimetallic ratiometric luminescence sensor realized accurate, high sensitivity (LOD is 1.03 × 10−6 M) and high selectivity detection of DPA. Due to the simple synthesis method and low technical requirements, this work provides a good strategy for the development of simple and effective bimetallic ratiometric luminescence sensors.