Tb-MOF-based luminescent recovery probe for rapid and facile detection of an anthrax biomarker

Rapidly detecting 2, 6-dipicolinic acid (DPA, an anthrax biomarker) in a highly sensitive manner is vital due to DPA being highly lethal to human beings and animals. However, most reported DPA probes are "turn-on' type, while luminescent recovery probes (LRPs) are still rare. Herein, a unique Tb-MOF (1) LRP was tailor-made, and its function is achieved via an energy transfer regulation strategy. In 1, the characteristic luminescence from Tb3+ is not sensitized due to the lack of energy transfer from the carefully chosen ligand that also induces steric effects to allow solvent molecules to be coordinated to Tb3+. During detection, DPA replaces the solvent molecules and thus effectively sensitizes the emission from Tb3+, achieving recovery response. 1 exhibits highly selective sensing of DPA down to 1.7 mu M, and displays an obvious luminescence color change visible to naked eyes. Furthermore, a regular smartphone platform installed with a Color Recognizer App can achieve sensitive, realtime, and on-site detection of DPA. The probe can also be used for the effective detection of DPA in tap water, rainwater, and human serum. The work not only provides a route to the preparation of recovery probes but also proves the potential of such probes.