A non-enzymatic sensor based on rGO/Pt NPs/Fc-Tyr/POPD nanocomposite for hydrogen peroxide determination in liver cancer tissues.

Malignant tumors remain a major global health challenge, highlighting the need for rapid and sensitive analytical tools for investigating cancer-associated oxidative stress. In this study, we developed a non-enzymatic electrochemical hydrogen peroxide (H₂O₂) sensor based on a reduced graphene oxide/platinum nanoparticle/ferrocene-tyramine/poly(o-phenylenediamine) (rGO/Pt NPs/Fc-Tyr/POPD) nanocomposite. H₂O₂, although not a tumor-specific biomarker, is an important reactive oxygen species associated with oxidative stress in cancer-related systems. The proposed sensing platform integrates the high conductivity of rGO, the electrocatalytic activity of Pt NPs, the TSA-derived Fc-Tyr deposition strategy, and the anti-interference properties of POPD. The sensor exhibited two wide linear detection ranges (5.0 µM-570 µM and 570 µM-10.5 mM), a low detection limit of 1.18 µM, and a rapid response time of less than 5 s. In addition, the sensor demonstrated satisfactory selectivity, reproducibility, and stability. Compared to previously reported rGO/Pt-based H₂O₂ sensors, the present platform introduces a TSA-derived Fc-Tyr deposition strategy to facilitate interfacial electron transfer and increase the density of redox-active species. The sensor was successfully applied to monitoring H₂O₂ changes in cultured cancer cells and ex vivo tumor tissue-derived samples under chemically stimulated oxidative conditions. These findings suggest that the proposed system may provide a useful tool for investigating oxidative-stress-associated biological processes and electrochemical H₂O₂ determination.