A reaction based one- and two-photon fluorescent probe for selective imaging H2O2 in living cells and tissues

•Novel fluorescent probe for H2O2 employed enamine as response group was designed and synthesized.•The probe GC-2 exhibited good sensitivity and satisfactory selectivity for discrimination of H2O2.•The probe GC-2 showed good OP and TP fluorescence imaging capability in living cells and tissues with low cytotoxicity.

Hydrogen peroxide (H2O2) exists extensively in mammalian cells as an active and significant by-products in bio-metabolism and plays vital roles in normal physiological activities and the occurrence of many diseases. Thus, development of fluorescence probes for monitoring H2O2 is profound for the diagnosis and treatment of these diseases. Other than previous reported fluorescence probes for H2O2, we proposed a two-photon fluorescence probe GC-2 possessing an original response enamine group, which can undergo the cleavage of carbon-carbon double bond by H2O2 and result in the appearance of blue fluorescence due to Intramolecular Electron Transfer (ICT). The probe GC-2 exhibited satisfactory sensitivity to H2O2 with the limitation of detection (LOD) of 2.1 × 10−7 M, and displayed good selectivity to H2O2 from other ROS and amine acids under physiological pH conditions. Remarkably, our probe GC-2 showed admirable one- and two- photon fluorescence imaging capability in living cells and tissues with low cytotoxicity. In a word, the rational designed probe has tremendous potential for monitoring H2O2 in living systems utilizing the one- and two- photon fluorescence imaging.