Detection of singlet oxygen and superoxide anion with the fluorescence of FCLA

Abstract

Reactive oxygen species (ROS) plays a major role in various life systems and is critical in understanding the mechanisms of photodynamic therapy (PDT), seed vigour and plant stress, and so on. Researchers have dedicated much effort for detecting singlet oxygen and suqeroxide anion. FCLA (the fluoresceinyl cypridina luciferin analog) is a singlet oxygen and superoxide anion specific chemiluminescence probe. Typical chemiluminescence signal is relatively weak and its detection at single cell level is rather difficult. In the present study, the fluorescence of FCLA at 515 nm was investigated and was found to increase significantly during the ROS oxidative reaction. With fluorescence imaging technique, ROS can be detected by evaluating the spatial distribution and the dynamic changes in FCLA fluorescence. The technique is proved to have high sensitivity and excellent signal-to-noise ratio compared to direct CL measurement. With minimal cytotoxicity and excellent ROS selectivity, the FCLA fluorescence imaging technique can be a powerful new means in real-time in vivo and in situ single oxygen detection at the single cell level.