Porphyrin-based porous organic framework: An efficient and stable peroxidase-mimicking nanozyme for detection of H2O2 and evaluation of antioxidant

As promising alternatives to natural enzymes, catalytically active nanomaterials (nanozymes) are of great interest due to their high activity, controlled synthesis, low-cost, and excellent stability against stringent conditions. Studies of the chemical interactions between antioxidants and nanozymes would provide valuable information about catalytic mechanisms, help to better understand some metabolic pathways and screen more effective artificial enzymes. In this work, a porphyrin-based porous organic polymer, named FePPOP-1 was synthesized via a Sonogashira-Hagihara coupling reaction between 1,3,5-triethynylbenzene and iron 5,10,15,20-tetrakis-(4'-bromophenyl) porphyrin (FeTBrPP). FePPOP-1 possesses large BET surface area as well as high thermal and chemical stability. The good peroxidase-like activity of FePPOP-1 was confirmed by catalyzing the oxidation reaction of 3,3', 5,5'-Tetramethylbenzidine (TMB) with H2O2. A FePPOP-1 based colorimetric biosensor was then established for H2O2, glucose and three antioxidants [ascorbic acid (AA), gallic acid (GA) and tannic acid (TA)] detection with high sensitivity and stability. Moreover, the inhibitory effects of these three natural antioxidants on peroxidase-like activity of FePPOP-1 and the relative strength of their anti-oxidative capacity were comparatively investigated. The distinguishing inhibitory behavior of AA, GA and TA implied their different anti-oxidative mechanisms.