Gadolinium-based metal-organic framework with restriction of aggregation-caused quenching effect synergized...

Trace kanamycin (KAN) residues in animal-derived foods pose a significant threat to public health. A multiplex self-enhanced electrochemiluminescence (ECL) sensor was constructed based on gadolinium-based metal-organic framework (Gd-MOF) with restricted aggregation-caused quenching (ACQ) effect, synergistically integrated with actively catalytic platinum‑nitrogen‑carbon single-atom catalyst (Pt-N-C SAC), enabling specific detection of KAN. Gd-MOF was synthesized via the eight-coordinate assembly between Gd³⁺ and 9,10-di(p-carboxyphenyl)anthracene (DPA). The rigid framework of Gd-MOF inhibited the π-π stacking of DPA through steric hindrance, thereby restricting the ACQ effect. Meanwhile, the coordination interaction with Gd³⁺ ions and the spatial confinement within the Gd-MOF framework effectively restricted the intramolecular motion of DPA, leading to reduced non-radiative energy dissipation. Owing to the dual effects, the ECL efficiency of the Gd-MOF was significantly enhanced. Atomically dispersed Pt active sites exhibited remarkable catalytic activity by lowering the activation energy barrier of the OO bond in PDS, thereby accelerating the generation of highly reactive SO₄^-• radicals. Gd-MOF and Pt-N-C SAC were combined through electrostatic self-assembly, resulting in intimate interfacial coupling that increased the loading capacity of Gd-MOF and improved the conductivity of Pt-N-C SAC@Gd-MOF. This synergistic integration enabled self-enhanced ECL through combining multiple enhancing effects of Pt-N-C SAC. Combined with molecularly imprinted polymer (MIP) with high binding affinity and selective target recognition capability, the fabricated MIP-ECL sensor exhibited wide linear detection range of 1-10,000 nM and low limit of detection of 0.71 nM. This multiple self-enhanced modulation strategy provided novel approach for ECL sensing detection of KAN in food and the environment.