PSP is a two-photon fluorescent probe for hydrogen polysulfide (H2Sn), a reactive sulfur species (RSS) formed during ferroptosis.1 Upon reaction with H2Sn, the 2-fluoro-5-nitro-benzoate quenching group of PSP is removed, resulting in the release of a near-infrared emitting product. PSP is selective for H2Sn over a panel of reactive oxygen species (ROS), reactive nitrogen species (RNS), metal ions, and sulfur-containing ions. It has been used to detect H2Sn in live cells and tumor spheroids in vitro.
1.Di, X., Ge, C., Liu, Y., et al.Monitoring hydrogen polysulfide during ferroptosis with a two-photon fluorescent probeTalanta232122467(2021)