Fluorogenic toolbox for facile detecting of hydroxyl radicals: From designing principles to diagnostics applications

Reactive oxygen species (ROS) are a class of active substances containing oxygen, which widely exist in biological entities and natural environment. Among them, hydroxyl radicals (•OH) exhibit a strong tendency to capture electrons from nearby molecules. They react with DNA, amino acids, polysaccharides, and other biological molecules, in a diffusion-controlled manner. Moreover, excessive •OH is associated with diseases, such as cancer, diabetes, and neurodegenerative diseases. Therefore, detection and measurement of •OH are crucial. Electrochemical, electron paramagnetic resonance, and fluorescence methods are common ways to achieve this goal. Among them, the fluorescence method is widely used because of its high sensitivity and facile operation. In this paper, the design principles and diagnostic applications of various detection methods for •OH are reviewed.