Potassium‐Based Metal‐Organic Framework with Coordination‐Induced Electrochemiluminescence for Biosensing Applications

Abstract Tetraphenylethene (TPE) exhibits aggregation‐induced electrochemiluminescence (AIECL), but the achievement of high emission efficiency requires effective suppression of non‐radiative transitions. Herein, a cyclodextrin‐tetraphenylethene metal‐organic framework (CT‐MOF) is constructed that significantly enhances electrochemiluminescence (ECL) output via coordination‐induced electrochemiluminescence (CIECL). In the CT‐MOF, alkali metal ions K + coordinate with ligands comprising covalently linked amino‐ β ‐cyclodextrin ( β ‐CD) and carboxylated tetraphenylethene (TPE‐COOH), which reduces the dihedral angles of the TPE units and restricts their intramolecular rotation. The resulting rigid structure can suppress the non‐radiative pathways and generate a high ECL emission at low potential (0–1.1 V vs Ag/AgCl). Notably, the introduction of FeNi alloy‐modified graphdiyne quantum dots (FN‐GQDs) as the co‐reactant accelerators can induce further signal amplification. Taking advantage of the enhanced hydrophilicity of CT‐MOF, a nanobody‐based sandwich immunosensor is constructed for sensitive detection of tumor necrosis factor‐like cytokine 1A (TL1A), a key colitis biomarker. This work represents the first demonstration of integrating K + ‐coordinated MOFs with TL1A‐specific nanobodies for high‐performance ECL biosensing.