Design of a two-photon fluorescent probe for ratiometric imaging of endogenous hypochlorite in mitochondria

Hypochlorite (ClO−) is associated with complex physiological activities in the living system. Therefore, it is necessary to develop a tool for visualizing ClO− at the cellular and subcellular levels. We herein presented a two-photon fluorescent probe MCL with dual response sites and ratiometric response to ClO−. The response sites of two oxathiolane rings endowed probe MCL with superior selectivity for ClO− over other analytes. The fast response and high sensitivity of MCL to ClO− were also well demonstrated. In addition, probe MCL was confirmed to possess accurate mitochondrial targeting ability through a co-localization study. The good two-photon sensing performance of MCL for exogenous and LPS-induced endogenous ClO− in living cells was validated by dual-color imaging. Moreover, we employed the probe to successfully monitor endogenous ClO− in H2S-stimulated cells by dual-channel mode for the first time. A two-photon fluorescent probe with dual response sites for ratiometric imaging of mitochondrial hypochlorite in living cells has been developed. [Display omitted] •A ratiometric two-photon fluorescent probe was designed for monitoring ClO−.•The probe showed ultrafast response and high selectivity for ClO− detection.•Dual-channel imaging of exogenous and endogenous ClO− in mitochondria was obtained.•The probe was used for dual-color imaging of H2S-induced ClO− in cells for the first time.