Biomimetic Peroxidase Model: Copper–Organic Framework Material Constructed with a Low-Symmetry Triazine Polycarboxylate Ligand for Visual Application as a Biosensing Platform

Metal-organic frameworks (MOFs) have recently emerged as fascinating enzymatic mimics due to their active metal-redox centers and attractive structural adjustability. However, the design of MOFs based on low-symmetry triazine polycarboxylate ligands as peroxidase-like mimics remains largely unexplored. Herein, a novel Cu-MOF (complex 1) was prepared using [5,5'-((6-(bis(carboxymethyl)amino)-1,3,5-triazine-2,4-diyl)bis(azanediyl))diisophthalic acid, H₆BATD] by a solvothermal method. Complex 1 presented a better affinity for the hydrogen peroxide substrate compared with the natural horseradish peroxidase (HRP) enzyme. Its peroxidase-like activity is related to the production of hydroxyl radicals (•OH) and superoxide radicals (•O₂^-), and the brief conversion mechanism is speculated based on XPS data. Based on this, the colorimetric method was utilized for the detection of H₂O₂ and partial biological molecules, especially ascorbic acid (AA) and glutathione (GSH), and the detection limits were as low as 0.38 μM for AA and 0.44 μM for GSH. In addition, smartphone-assisted recognition for AA sensing was realized, and complex 1 was employed as a peroxidase nanozyme for AA detection in fruits and pharmaceuticals. These findings not only throw light on the construction of MOFs with high enzyme-like activity but also on the structural expansion of novel MOFs based on a low-symmetry family of triazine derivative linkers.