A novel
electrochemical hydrogen peroxide (H2O2) sensor
based on Cu-porphyrin(Cu-TCPP)/G-quadruplex-hemin nanocomposite
was constructed by assembling two-dimensional Cu-TCPP metal–organic
framework (MOF) nanofilm and G-quadruplex-hemin DNAzyme. The Cu-TCPP
synthesized by the surfactant-assisted method has a wrinkled two-dimensional
nanofilm morphology, which gives it a large surface area and accessible
active sites. Cu-TCPP exhibits peroxidase activity and good stability
and can catalyze the reduction of H2O2. In addition,
Cu-TCPP can be used as a nanocarrier for G-quadruplex-hemin DNAzyme
with strong peroxidase activity to achieve “biological barcode”
amplification and improve stability. The cooperative interaction of
Cu-TCPP and G-quadruplex-hemin DNAzyme effectively amplifies the electrochemical
response signal. Electrochemical studies have shown that the constructed
sensor exhibits good electrochemical sensing performance with three
linear ranges: 0.08 μM to 0.11 mM, 0.11–0.91 mM, and
0.91–8.1 mM, with sensitivities of 2315.86, 301.00, and 65.71 μA/(mM
cm2), respectively, and the detection limit was 0.03 μM.
In addition, the sensor shows good selectivity. In summary, this study
provides a simple and effective new strategy for electrochemical sensing
based on two-dimensional MOFs and artificial enzymes.