Europium Metal-Organic Framework with a Tetraphenylethylene-Based Ligand: A Dual-Mechanism Quenching Immunosensor for...

The effective applications of electrochemiluminescence (ECL) across various fields necessitate ongoing research into novel luminophores and ECL strategies. In this study, self-luminous flower-like nanocomposites (Eu-tcbpe-MOF) were prepared by coordination self-assembly using the aggregation-induced emission material 1,1,2,2-tetrakis(4-carboxyphenyl)ethylene (H₄TCBPE) and Eu(III) ions as the precursors. Compared with the monomers and aggregates of H₄TCBPE, Eu-tcbpe-MOF exhibits stronger ECL emission. Such enhanced electrochemiluminescence is due to coordination as the coordination-triggered electrochemiluminescence (CT-ECL) enhancement effect. In this study, a cubic-structured nanocomposite (Co₉S₈@Au@MoS₂) was used as an efficient quencher, and a more sensitive ECL detection platform was achieved by two quenching mechanisms: resonance energy transfer and competitive consumption of coreactants. N,N-Diethylethanolamine (DBAE) was used as a coreactant, and DBAE has a faster electron transfer rate and stronger energy supply efficiency than the traditional anodoluminescent coreactant tripropylamine, which effectively improves the ECL signal intensity of Eu-tcbpe-MOF. Hence, a sandwich-type ECL immunosensor was prepared by employing a dual-quenching mechanism, utilizing Eu-tcbpe-MOF as the detection probe and Co₉S₈@Au@MoS₂ as the quencher, achieving precise detection of carcinoembryonic antigen from 0.1 pg·mL^-1 to 100 ng·mL^-1 with a detection limit of 35.1 fg·mL^-1.