Self-supporting electrochemical sensors for monitoring of cell-released H2O2 based on metal nanoparticle/MOF nanozymes

Metal−organic frameworks (MOFs) can be used as Supporting Materials to support metal nanoparticles for enhanced electrocatalytic performance. In this work, electrodeposition of metal nanoparticles (NPs) on the zinc-based metal–organic frameworks (Zn-MOFs) with two types of morphologies was fabricated to develop a self-supporting electrochemical sensor. First, among the common metal nanoparticles, AgNPs has the best electrocatalytic activity than PtNPs and AuNPs towards H2O2 reduction. Secondly, the influences of different dimensions on the electrocatalytic activity of Zn-MOFs as Supporting Material were investigated. AgNPs modified two-dimensional Zn-MOFs (Ag/2D Zn-MOFs) exhibited better electrocatalytic activity than the AgNPs modified three-dimensional Zn-MOFs (Ag/3D Zn-MOFs). 2D MOFs can improve the dispersion and stability of the active metal components, provide a large specific surface area, and enhance high electrical conductivity. Under the optimal conditions, the Ag/2D Zn-MOFs modified electrodes displayed a low detection limit of 1.67 μM (S/N = 3) with a wide linear range from 5.0 μM to 70 mM. In addition, the modified electrode was evaluated for the real-time detection of H2O2 from living (normal and tumor) cells in response to the specifically drug-stimulated process. This metal nanoparticle/MOF nanozymes-based sensor can be used as an ideal platform for detecting biomarkers and drug evaluation.