Oxygen Vacancy Engineering and Synergistic Electrocatalysis of NiFe-LDH for Boosting Coordination Aggregation-Induced Electrochemiluminescence of Zr-MOF to Detect Heart-Type Fatty Acid Binding Protein

The development of high-performance electrochemiluminescence (ECL) biosensors is often hindered by the intrinsically weak and unstable ECL emission of organic luminophores. To address this challenge, we propose a novel strategy that integrates coordination aggregation-induced ECL (CAIECL) with bimetallic synergistic electrocatalysis to significantly boost the ECL emission. A zirconium-based metal−organic framework (Zr-MOF) was synthesized by coordinating zirconium ions with an aggregation-induced emission (AIE) molecule 1,1′-binaphthalene-4,4′-dicarboxylic acid (BDA). This coordination not only restricted the intramolecular motion of BDA but also reduced its band gap, leading to significant enhancement in ECL performance compared to the BDA monomer. To further amplify the signal, an oxygen vacancy nickel-iron layered double hydroxide (NiFe-LDH) was introduced as a co-reaction accelerator. The synergistic electrocatalytic conversion of S 2 O 8 2 − to SO 4 •− by the variable valence metal ions (Ni 3+ /Ni 2+ and Fe 3+ /Fe 2+ ) within NiFe-LDH further augments the ECL performance of the Zr-MOF. Leveraging this highly efficient ECL system, a high-performance ECL immunosensor was created for the sensitive analysis of heart-type fatty acid binding protein (H-FABP). This sensor utilized ZIF-8@CCM@AuNPs as the quencher, which suppressed the ECL emission of the Zr-MOF through a dual quenching mechanism involving free radical scavenging and ECL resonance energy transfer (ECL-RET). The proposed biosensor exhibited excellent analytical performance with a wide linear range (10 fg/mL to 200 ng/mL) and detection limit of 2.4 fg/mL. This work presents a versatile strategy for designing high-performance ECL materials and highlights their great potential for advanced bioanalysis.