Oxidation of fluorogenic probes detecting reactive oxygen species in the extracellular medium

DCF-DA) in cell culture and cell-free media was compared. Comparable or higher oxidation rates in cell-free medium were found for all probes. These results point to autoxidation of redox-active components of the medium as the main cause of changes in the properties of cell culture media and suggest that the intracellular oxidation of the probes may also be partly due to their autoxidation.