Electron spin resonance and fluorescence imaging assisted electrochemical approach for accurate and comprehensive monitoring of cellular hydrogen peroxide dynamics.

Dynamic alteration in the levels of cellular hydrogen peroxide (H2 O2 ) is closely related to a variety of human diseases, as well as signal transduction pathways that regulate cell survival and death. Although qualitative or quantitative methods are available for measuring either intra- or extra-cellular H2 O2 levels, accurate and comprehensive in situ detection of the real-time H2 O2 dynamics of living cells remains a significant challenge. To solve this problem, a novel multi-dimensional in situ cell assay platform combining electrochemistry, electron spin resonance (ESR) and optical imaging is designed. In this platform, the real-time concentration of extracellular H2 O2 released from stimulated cells can be accurately detected by ESR assisted chronoamperometry, while the level of intracellular H2 O2 is simultaneously monitored via the incorporated fluorescence imaging. Accurately and simultaneously analyzing the level variations of extra- and intra-cellular reactive oxygen species based on our assay platform can complement each other for further precise and in-depth investigation of their membrane transport and related cellular signaling, which will benefit disease diagnosis and treatment.