A lanthanide metal organic frameworks ratiometric fluorescence sensor for visual detection of anthrax biomarker

A novel dual-emission fluorescence probe, Eu-TDA-DHTP, was developed based on a ratiometric fluorescence-organic frameworks utilizing Eu³⁺, 2,5-Thiophenedicarboxylic acid, and 2,5-dihydroxyterephthalic acid for the ratiometric and fluorescent visual sensing of the anthrax biomarker 2,6-pyridine dicarboxylic acid (DPA). The experiments demonstrated that this material can effectively enhance dual emission for DPA detection, enabling clear visualization. The limit of detection for DPA detection using Eu-TDA-DHTP is 1.9 μmol/L in fluorometric mode and 5 μmol/L in colorimetric mode. Additionally, the preparation of the Eu-TDA-DHTP@PVP composite matrix membrane and the development of a smartphone-assisted visual assay have enhanced the convenience of DPA detection in serum and urine samples. This study presents a sensitive, efficient, and user-friendly platform for the visual monitoring of DPA, an anthrax biomarker, in real samples.