Chromogenic, Fluorescent, and Redox Sensors for Multichannel Imaging and Detection of Hydrogen Peroxide in Living Cell Systems

Hydrogen peroxide (H2O2) is an important reactive oxygen species (ROS). Maintaining the H2O2 concentration at a normal level is critical to achieve the normal physiological activities of cells, which otherwise might trigger various diseases. Therefore, it is necessary to develop new and practical multisignaling sensors for both visualization of intracellular H2O2 and accurate detection of extracellular H2O2. In this paper, a novel multichannel signaling fluorescence electrochemistry combined probe 1 (FE-H2O2) is presented for imaging and detection of H2O2 in living cell systems. In our design, the probe FE-H2O2 consists of a H2O2 reaction site and 4-ferrocenyl(vinyl)pyridine unit which affords chromogenic, fluorescent, and electrochemical signals. These structural motifs yield a combined chromogenic, fluorescent, and redox sensor in a single molecule. Probe FE-H2O2 showed a "Turn-On" fluorescence response to H2O2, which can be used for monitoring intracellular H2O2 in vivo. Furthermore, the electrochemical response of probe FE-H2O2 was decreased after the addition of H2O2, which can be applied for accurate detection of H2O2 released from living cells. When the fluorescence imaging method is combined with electrochemical analysis technology, it is hopeful that the well-designed multimodule probe can serve as a practical tool for understanding the metabolism and homeostasis of H2O2 in a complex biological system.