Self-supported Au–CoMn2O4/Ni foam heterostructure sensor for efficient H2O2 detection and real-time tumor biomarker monitoring

Hydrogen peroxide (H₂O₂) is a crucial oxidative stress biomarker associated with various diseases, especially tumor progression and inflammatory disorders. Accurate monitoring of H₂O₂ is essential for understanding the microenvironmental dynamics involved in disease development. However, traditional metal oxide-based electrochemical sensors often suffer from low catalytic efficiency and nanoparticle aggregation. Herein, we report a high-performance, binder-free H₂O₂ sensor based on a rationally engineered Au–CoMn₂O₄/Ni foam heterostructure. This integrated architecture leverages the conductive 3D Ni foam and an interface-mediated interaction-enhanced charge transfer interface to significantly enhance sensing performance. The resulting sensor exhibits two sensitivities, 3100.04 μA·mM⁻¹·cm⁻² (2–666 μM) and 821.41 μA·mM⁻¹·cm⁻² (1.066–22.166 mM), an ultralow detection limit of 0.036 μM, and a practical linear detection range spanning 2 μM–22.166 mM (R² = 0.99). It also demonstrates excellent selectivity, long-term stability (<3% signal decay over 30 days), and reproducibility (RSD ≈ 2.5%). Notably, the sensor enables real-time electrochemical monitoring of H₂O₂ released by A549 lung cancer cells under phorbol 12-myristate 13-acetate (PMA) stimulation, highlighting its potential as a platform for advanced electrochemical sensing. Importantly, the sensing mechanism can be well interpreted via interfacial structure analysis and electrochemical validation, without requiring theoretical simulations.