Triple Optimization of Yttrium‐Doped Lanthanide MOF: Polarized Nanochannels Driving Norfloxacin Turn‐On Sensing and Background‐Free Cell Imaging

Abstract To address environmental and health risks from antibiotic abuse, this study develops a highly sensitive detection probe using a Y 3+ heavy‐doping strategy in Eu‐MOF. The approach achieves triple optimization: structural stabilization, energy transfer enhancement, and pore polarization. Y 3+ doping creates single‐ion dispersed Eu 3 ⁺ nodes, suppressing concentration quenching and improving charge transfer. The dipole moment increases to 8.7239 debye , strengthening norfloxacin (NOR) adsorption (−157.65 kcal mol −1 binding energy). The resulting 334.8 nm particles show reduced cytotoxicity (IC 50 : 76.66 µM). The Eu 0.2 Y 0.8 ‐BTB probe achieves a 0.4058 µM NOR detection limit (10.8× more sensitive than undoped systems) with high selectivity. Theoretical simulations reveal synergistic weak interactions and coordination bonding activate dual‐path energy transfer: the NOR → Eu 3+ antenna effect extends fluorescence lifetime (189.68 → 460.76 µs), while coordination reduces the LMCT barrier by 64% (1.553 → 0.556 eV). The probe enables specific “Turn‐On” NOR imaging in cells, leveraging Eu 3+ 's large Stokes shift (270 nm) to avoid background interference. This work provides a new paradigm for developing ultra‐sensitive, biocompatible lanthanide MOF‐based diagnostic platforms.