Two-Dimensional Nanozyme Based on Iron Metal–Organic Gel/Carboxylated Graphene Oxide for Electrochemical and Colorimetric Dual-Mode Detection of Hydrogen Peroxide

Metal–organic gel (MOG) is a distinctive metal–organic hybrid material with a unique porous structure and exceptional catalytic site accessibility. The rational design of an electrochemical and colorimetric dual-mode sensor platform utilizing the peroxidase (POD)-like activity of MOG for the detection of H 2 O 2 is crucial for clinical diagnosis. In this article, a two-dimensional composite nanozyme based on Fe-MOG and carboxylated graphene oxide (GO-COOH) was synthesized, which serves dual functions to establish electrochemical sensing and colorimetric sensing based on its excellent electrocatalytic reduction of H 2 O 2 and POD-like activity. GO-COOH played a critical role, and the electrochemically reduced ERGO-COOH facilitated electron transfer from the metal catalytic site in Fe-MOG, enhancing the performance of electrocatalytic reduction of H 2 O 2 . Additionally, GO-COOH amplified the POD-like activity of Fe-MOG, and the Fe-MOG/GO-COOH composite participated in various ROS-mediated catalytic reactions. The developed dual-mode sensor exhibited a rapid response and high sensitivity in detecting H 2 O 2, demonstrating excellent selectivity, reproducibility, and stability. These attributes enhanced the accuracy and reliability of the detection of H 2 O 2 released from living cells. This MOG-based nanozymatic dual-mode sensing technology offers promising prospects for enhancing the reliability of rapid detection and holds significant potential for application in pathophysiological monitoring of living cells.