A non-enzymatic hydrogen peroxide biosensor based on cerium metal-organic frameworks, hemin, and graphene oxide composite

This study presents the development of a novel non-enzymatic electrochemical biosensor for the real-time detection of hydrogen peroxide (H₂O₂) based on a composite of cerium metal–organic frameworks (Ce-MOFs), hemin, and graphene oxide (GO). The Ce-MOFs served as an efficient matrix for hemin encapsulation, while GO enhanced the conductivity of the composite. Characterization techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, UV–vis spectroscopy, and thermogravimetric analysis (TGA) confirmed the successful integration of hemin into the Ce-MOFs. The Ce-MOFs@hemin/GO-modified sensor demonstrated sensitive H₂O₂ detection due to the exceptional electrocatalytic activity of Ce-MOFs@hemin and the high conductivity of GO. This biosensor exhibited a linear response to H₂O₂ concentrations from 0.05 to 10 mM with a limit of detection (LOD) of 9.3 μM. The capability of the biosensor to detect H₂O₂ released from human prostate carcinoma cells was demonstrated, highlighting its potential for real-time monitoring of cellular oxidative stress in complex biological environments. To further assess its practical applicability, the sensor was tested in human serum samples, yielding promising results with recovery values ranging from 94.50 % to 103.29 %. In addition, the sensor showed excellent selectivity against common interfering compounds due to the outstanding peroxidase-like activity of the composite.