Highly Sensitive Detection of Hydrogen Peroxide in Cancer Tissue Based on 3D Reduced Graphene Oxide–MXene–Multi-Walled Carbon Nanotubes Electrode

Hydrogen peroxide (H₂O₂) is a signaling molecule that has the capacity to control a variety of biological processes in organisms. Cancer cells release more H₂O₂ during abnormal tumor growth. There has been a considerable amount of interest in utilizing H₂O₂ as a biomarker for the diagnosis of cancer tissue. In this study, an electrochemical sensor for H₂O₂ was constructed based on 3D reduced graphene oxide (rGO), MXene (Ti₃C₂), and multi-walled carbon nanotubes (MWCNTs) composite. Three-dimensional (3D) rGO-Ti₃C₂-MWCNTs sensor showed good linearity for H₂O₂ in the ranges of 1-60 μM and 60 μM-9.77 mM at a working potential of -0.25 V, with sensitivities of 235.2 µA mM^-1 cm^-2 and 103.8 µA mM^-1 cm^-2, respectively, and a detection limit of 0.3 µM (S/N = 3). The sensor exhibited long-term stability, good repeatability, and outstanding immunity to interference. In addition, the modified electrode was employed to detect real-time H₂O₂ release from cancer cells and cancer tissue ex vivo.