Dual-source signal amplification electrochemiluminescence sensor combined with molecularly imprinted polymers for the...

A novel lanthanide metal-organic-gel (MOG)-derived material/nitrogen-doped graphdiyne (Tb-Ru-MOG/CeO₂/N-GDY) composite with a dual-source signal amplification strategy was prepared and used to construct a molecularly imprinted sensor based on bifunctional monomers for the detection of imidacloprid (IMI) using electrochemiluminescence (ECL). In a green reaction environment, terbium (III) (Tb³⁺) can undergo multiple coordination reactions with 4'-(4-carboxyphenyl)-2,2':6',2″-terpyridine (Hcptpy) and tris(4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium (II) dichloride (Ru(dcbpy)₃²⁺), and combine with ceria nanoparticles (CeO₂ NPs) to form Tb-Ru-MOG/CeO₂. Within the Tb-Ru-MOG/CeO₂ framework, energy transfer from the double ligands can sensitize the central Tb³⁺, triggering a distinct antenna effect and energy-transfer, and its polyporous configuration offered a nanoconfined space for Ce³⁺/Ce⁴⁺ to effectively catalyze coreactant radicals (S₂O₈^2-), leading to in-situ endogenous activation ECL reactions. The conductive N-GDY accelerated electron movement and increased the loading on the electrode surface, enhancing the exogenous excitation of the ECL signals. Leveraging the synergistic effect of the bifunctional monomer, the synthesized molecularly imprinted polymers (MIPs) ECL sensor demonstrated a wide detection range from 10 nM to 10,000 nM for IMI, with a limit of detection (LOD) of 1.37 nM, showcasing an innovative concept for the dual-source strategy of signal amplification in integrated ECL composites to analyze food and environmental hazards.