Terpyridine-tricarboxylate-based Eu(III)/Tb(III) MOFs for selective turn-off luminescent detection of tetracycline and ATP with smartphone-assisted sensing and latent fingerprint visualization

The development of selective and sensitive photoluminescent sensors for detecting biomolecules and antibiotics remains a significant challenge. In this study, two highly stable lanthanide-based metal organic frameworks (MOFs) with the general formula {[Ln₂(L1)₃(H₂O)]·2H₂O}ₙ (Ln = Eu 1 , Tb 2 ) have been synthesized solvothermally using rigid tritopic ligand 2-([2,2′:6′,2″-terpyridin]-4′-yl)benzene-1,3,5-tricarboxylic acid (H₃L1). Single-crystal X-ray diffraction studies reveal that these MOFs exhibit a robust three-dimensional network stabilized by π···π stacking interactions and syn–syn carboxylate bridging present, with the lanthanide centers adopting bicapped square antiprism (BCSAP) geometry. These MOFs have been used as turn-off photoluminescent sensors for the sensitive and selective detection of antibiotics and the studies reveal that MOFs 1 and 2 showcase highly effective luminescent sensing of tetracycline (TCY) with limit of detection (LOD) 1.04 × 10⁻⁵ M and 7.24 × 10⁻⁶ M, respectively. Also, both 1 and 2 exhibit turn-off photoluminescent sensing against adenosine triphosphate (ATP) with LOD 5.57 × 10⁻⁵ M and 4.00 × 10⁻⁵ M, respectively. Both 1 and 2 have been further integrated into a smartphone-assisted platform for visual detection of TCY and ATP, enhancing its practical applicability. In addition, both MOFs have been successfully applied in the visualization of latent fingerprints (LFPs), highlighting their potential utility in forensic science. The sensors exhibit excellent performance in real sample analyses (milk, honey, egg and pork), with recovery rates ranging from 82% to 115% and relative standard deviations (RSDs) between 0.18% and 1.58%. These results demonstrate that 1 and 2 are promising multifunctional material for practical applications in biochemical sensing and forensic diagnostics.