Tuning Ligand Defect in Porphyrins Metal-Organic Frameworks to Boost Electrochemiluminescence for Sensitive Detection of Amyloid-Β1-42

Abstract

Defect engineering in metal-organic frameworks (MOFs) endows electrochemiluminescence (ECL) enhancement windows. This work pioneers a ligand defect levels modulation strategy to control the ECL performance of porphyrin-MOFs (PCN-224). By altering the amount of benzoic acid (BA), we reveal a distinct volcano-like relationship between defect levels and ECL intensity. Among a series of PCN-224 samples with varying ligand defect levels, PCN-224-130BA demonstrates the best performance, exhibiting an ECL intensity 5.34-fold higher than that of 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) aggregates. Experimental results unveil that the existence ligand defects can accelerate the interfacial electron transfer kinetics and enhance the activation of co-reactant S2O82−, as well as improve electron-hole recombination efficiency of the PCN-224/S2O82− system, leading to significant improvement in ECL performance. In proof-of-concept ECL application, a sandwich-type immunosensor was developed and applied for the detection of amyloid-β1-42 with good selectivity and a limit of detection of 3.89 fg mL−1. This work elucidates the relationship between ECL intensity and ligand defect levels, providing crucial insights for achieving highly efficient ECL performance through the deliberate introduction of moderate structural defects in MOFs.

Keywords: Electrochemiluminescence, PCN-224, Ligand defect, Volcano-like relationship, Amyloid-β1-42