A portable and versatile rGO-Co ₃ O ₄ -Pt nanocomposite-based electrochemical sensor for <i>ex vivo</i> and <i>in vivo</i> cardiac oxidative stress monitoring

The excessive production of reactive oxygen species (ROS) disrupts redox homeostasis, contributing to the development of cardiovascular diseases. Among ROS, hydrogen peroxide (H₂O₂) serves as a key mediator of oxidative signaling and a critical biomarker of cellular oxidative damage due to its relative stability and signaling relevance. However, current detection strategies for ROS and H₂O₂ often lack the necessary sensitivity, selectivity, and real-time responsiveness, underscoring the urgent need for advanced sensing platforms to support precision cardiovascular medicine. The research introduces a ROS detection based on reduced graphene oxide-cobalt oxide-platinum (rGO-Co₃O₄-Pt) nanocomposites for biological sample analysis. The nanocomposite platform enables H₂O₂ detection down to 160 nM, with linearity up to 2.50 μM. The platform showed acceptable analytical performance in terms of sensitivity, repeatability, and selectivity, which enabled both <i>ex vivo</i> and <i>in vivo</i> H₂O₂ monitoring. The method was validated in doxorubicin (DOX)-induced cardiotoxicity models using HL-1 cells and C57BL/6J mice, showing strong correlation with MTT-based ROS assays. The rGO-Co₃O₄-Pt nanocomposite improves portable analytical devices for real-world pharmacological applications. The technology enables real-time therapeutic monitoring while optimizing individualized dosing and expanding its applications to cancer treatment and diabetes management and neurological disorders.