Methods for the detection of reactive oxygen species

There are many pieces of evidence suggesting the mediating role of reactive oxygen species (ROS) in cell life, stress and death, and it is known that ROS at different concentrations would play distinctly different roles therein, thus eventually leading to the different fates of cells. Therefore it is highly necessary to carry out a reliable measurement of the concentration or relative level of ROS. Many means are available for ROS detection, such as the classical and commonly used spectrophotometry methods, use of fluorescence and chemiluminescence probes, and electron spin resonance (ESR/EPR), which provide direct identification of different types of oxygen radicals. In addition, fluorescent protein-based redox indicators designed for monitoring redox status changes would also be introduced in the text. Considering the fact that each type of method mentioned above has drawbacks during application, the present review tries to make a comparison and summary of their advantages and disadvantages systemically, and as a conclusion, the rational use of more than one method is recommended for better testing of the free radicals in cells.