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 H2O2 released from stimulated cells can be accurately detected by ESR assisted chronoamperometry, while the level of intracellular H2O2 is simultaneously monitored via the incorporated fluorescence imaging. 
ESR