A novel Zn2+ complex as the ratiometric two-photon fluorescent probe for biological Cd2+ detection

• A novel Zn2+ complex as the ratiometric two-photon fluorescent probe (HQZn) for Cd2+ detection was reported.
• The HQZn exhibited good two-photon properties and high selectivity for Cd2+ (especially over Zn2+).
• The HQZn could be used for detecting intracellular Cd2+ with low cytotoxicity.

A novel Zn2+ complex as the ratiometric two-photon fluorescent probe (HQZn) for Cd2+ detection was synthesized. Fluorescence emission spectra of the probe showed a large red-shift (75 nm) and obvious enhancement of fluorescent intensity upon the addition of Cd2+. HQZn shows high selectivity for Cd2+ over other metal ions, and can eliminate the interference of Zn2+ during Cd2+ detection. Maldi-TOF MS spectra indicated that the response of HQZn to Cd2+ was caused by central metal displacement. Cell cytotoxicity and bio-imaging studies revealed that HQZn was cell-permeable and it could be used to detect intracellular Cd2+ with low cytotoxicity under two-photon excitation.

A novel Zn2+ complex as the ratiometic two-photon fluorescent probe (HQZn) for Cd2+ detection was synthesized.Figure optionsDownload as PowerPoint slide