A two-photon fluorescence probe for selective monitoring of superoxide in live cells and tissues.

The abnormal location or generation of superoxide radical anion (O-2(center dot-)) are implicated in many diseases, including cancers; thus, development of an efficient method to detect O(2)(center dot- )is of great importance. Inspired by the fluorophore-governed selective manner to O-2(center dot-) and peroxynitrite (ONOO-) of previously reported phosphinate-based fluorescence probes, in this contribution, a phosphinothioate-containing probe, TPP, was designed. The probe exhibited easy accessibility through a one-step sequence and good photostability and biocompatibility. Interestingly, TPP showed high specificity and sensitivity to O-2(center dot-) over other reactive oxygen species/nitrogen species including ONOO. Furthermore, with the assistance of two-photon microscopy, TPP was successfully applied for imaging endogenous O-2(center dot-) in live cells and tissues.