Amplified\nElectrochemical Hydrogen Peroxide Sensing\nBased on Cu-Porphyrin Metal–Organic Framework Nanofilm and\nG‑Quadruplex-Hemin DNAzyme

Abstract

A novel\nelectrochemical hydrogen peroxide (H₂O₂) sensor\nbased on Cu-porphyrin­(Cu-TCPP)/G-quadruplex-hemin nanocomposite\nwas constructed by assembling two-dimensional Cu-TCPP metal–organic\nframework (MOF) nanofilm and G-quadruplex-hemin DNAzyme. The Cu-TCPP\nsynthesized by the surfactant-assisted method has a wrinkled two-dimensional\nnanofilm morphology, which gives it a large surface area and accessible\nactive sites. Cu-TCPP exhibits peroxidase activity and good stability\nand can catalyze the reduction of H₂O₂. In addition,\nCu-TCPP can be used as a nanocarrier for G-quadruplex-hemin DNAzyme\nwith strong peroxidase activity to achieve “biological barcode”\namplification and improve stability. The cooperative interaction of\nCu-TCPP and G-quadruplex-hemin DNAzyme effectively amplifies the electrochemical\nresponse signal. Electrochemical studies have shown that the constructed\nsensor exhibits good electrochemical sensing performance with three\nlinear ranges: 0.08 μM to 0.11 mM, 0.11–0.91 mM, and\n0.91–8.1 mM, with sensitivities of 2315.86, 301.00, and 65.71 μA/(mM\ncm²), respectively, and the detection limit was 0.03 μM.\nIn addition, the sensor shows good selectivity. In summary, this study\nprovides a simple and effective new strategy for electrochemical sensing\nbased on two-dimensional MOFs and artificial enzymes.