Quantitative measurement of reactive oxygen species in vivo by utilizing a novel method: chemiluminescence with an internal fluorescence as reference

Abstract

Reactive oxygen species (ROS) produced by photodynamic therapy (PDT) is recorded in vivo using a chemiluminescence (CL-based gated optical system. A novel approach is developed to utilize the fluorescence (FL) of the CL probe as an internal fluorescence to calibrate the observed CL on pharmacokinetics of the probe in situ. The results show that during an in vivo PDT session, the intensity of CL decreases significantly and the decaying of CL is governed by fast and slow time components. By comparing the temporal profile of FL to that of the corresponding CL, it is found that the slow component is mainly attributed to the probe pharmacokinetics, whereas the fast component is likely due to rapid oxygen consumption as a result of PDT treatment. With carefully selected criteria, it is possible to minimize the effect of probe pharmacokinetics. This significantly improves the monitoring method for practical applications. © 2010 Society of Photo-Optical Instrumentation Engineers.