Colorimetric fluorescence determination of anthrax biomarker using a bimetallic lanthanide metal–organic framework

Abstract

Bacillus anthracis is toxic bacterial spore that cause human anthrax infections. Therefore, rapid and sensitive detection of Bacillus anthracis or its main biomarker 2, 6-pyridine dicarboxylic acid (DPA) is of great significance. Herein, a series of lanthanide–organic frameworks (Tb/Eu-MOF-1–6) were synthesized by the solvothermal reactions of 2,2′-bipyridine-6,6′-dicarboxylic acid (H2BPDC) with Eu3+ and Tb3+. Among these samples, Tb/Eu-MOF-6 exhibited selective detection of DPA with self-calibrating and colorimetric fluorescence determination. The sensitivity of Tb/Eu-MOF-6 revealed a linear response of ln (IN) = -10.896CDPA + 0.14366 with a limit of detection with 4.51 μM. The emission color of Tb/Eu-MOF-6 observed with the naked eye, turned yellow to red after introducing appropriate concentration of DPA.The energy-transfer behavior between BPDC2- Tb3+, and Eu3+ was systematically studied, which primarily controlled the sensitivity of detection. With the combined merits of self-calibrating, rapid and naked-eye recognition of DPA, Tb/Eu-MOF-6 can be counted as a promising contender for anthrax biomarker detection.