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

Hydrogen peroxide (H 2 O 2 ) is an important reactive oxygen species (ROS). Maintaining the H 2 O 2 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 H 2 O 2 and accurate detection of extracellular H 2 O 2 . In this paper, a novel multichannel signaling fluorescence–electrochemistry combined probe 1 (FE-H 2 O 2 ) is presented for imaging and detection of H 2 O 2 in living cell systems. In our design, the probe FE-H 2 O 2 consists of a H 2 O 2 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-H 2 O 2 showed a “Turn-On” fluorescence response to H 2 O 2, which can be used for monitoring intracellular H 2 O 2 in vivo. Furthermore, the electrochemical response of probe FE-H 2 O 2 was decreased after the addition of H 2 O 2, which can be applied for accurate detection of H 2 O 2 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 H 2 O 2 in a complex biological system.