Electrochemical Enzyme Sensor Based on the Two-Dimensional Metal-Organic Layers Supported Horseradish Peroxidase

Metal-organic frames (MOFs) have recently been used to support redox enzymes for highly sensitive and selective chemical sensors for small biomolecules such as oxygen (O₂), hydrogen peroxide (H₂O₂), etc. However, most MOFs are insulative and their three-dimensional (3D) porous structures hinder the electron transfer pathway between the current collector and the redox enzyme molecules. In order to facilitate electron transfer, here we adopt two-dimensional (2D) metal-organic layers (MOLs) to support the HRP molecules in the detection of H₂O₂. The correlation between the current response and the H₂O₂ concentration presents a linear range from 7.5 μM to 1500 μM with a detection limit of 0.87 μM (S/N = 3). The sensitivity, reproducibility, and stability of the enzyme sensor are promoted due to the facilitated electron transfer.