Electrochemical quantification of intracellular hydrogen peroxide using cobalt phthalocyanine modified carbon nanopipettes

As the most stable member of the reactive oxygen species (ROS), hydrogen peroxide (H₂O₂) serves as both the key signaling molecule and pathological mediator. Real-time monitoring and quantitative analysis of H₂O₂ at the individual cell level are highly needed to fully resolve the cellular heterogeneity and uncover H₂O₂ roles in cellular metabolism and disease progression. Herein, we reported an electrochemical nanosensor for H₂O₂ detection based on sulfonated cobalt phthalocyanine modified carbon nanopipettes, and achieved real-time monitoring and quantification of H₂O₂ in a single living HeLa cell. Meanwhile, the numerical simulation was also conducted to help understand the different current trends when monitoring the intracellular H₂O₂ in different cells. This work provided a new platform for single-cell electrochemical detection of H₂O₂, promoting the understanding of ROS related cellular processes under oxidative stress.