Interfacial Hydrogen Bond-Mediated Rigidification Strategy Coupled with Stepwise Antenna Effect for Ultrasensitive...

Lanthanide metal organic frameworks (Ln-MOFs) are promising electrochemiluminescence (ECL) emitters due to their unique lanthanide antenna effect. However, the vibrational modes of organic ligands significantly induce nonradiative transitions and the inherent poor conductivity of MOFs limits charge injection, which hinders the overall performance of the ECL sensor. Herein, we report an innovative high-performance ECL sensor based on conductive-matrix-accelerated and radical-mediated stepwise antenna effect. By integrating an aluminum based metal-organic gel (AlOG), rich in carboxyl groups from 4,4',4″-nitrilotribenzoic acid (NTB), with europium/terbium metal-organic framework nanorods (Eu/Tb-MOF NRs), a highly ordered and rigid hydrogen-bonding network (O-H···O/N) was precisely constructed at the composite interface. This ordered architecture effectively suppresses ligand vibrations while the AlOG network acts as an "electron highway", facilitating the synchronous reduction of ligands and coreactants to trigger a radical-driven reaction cascade. Simultaneously, ligands in both the Ln-MOFs and AlOG can function as efficient "antennas", exciting Eu³⁺/Tb³⁺ ions through a stepwise energy transfer process, thereby synergistically enhancing the ECL signal. Leveraging its excellent ECL performance, a highly sensitive biosensing platform was constructed for sensitive detection of zearalenone. The fabricated sensor demonstrates outstanding analytical performance with a detection limit as low as 6.615 × 10^-16 M, a wide linear range from 1 × 10^-15 to 1 × 10^-5 M, along with excellent selectivity, stability, and reproducibility. This work not only provides a reliable sensing platform for rapid mycotoxin monitoring but also offers a pioneering design strategy integrating interfacial structural engineering with conductive-matrix-accelerated radical pathways for developing high-performance Ln-MOF-based ECL systems.