An active fluorescent probe based on aggregation-induced emission for intracellular bioimaging of Zn2+ and tracking of interactions with single-stranded DNA.

A novel dual-sensing fluorescence probe L was designed and synthesized for highly selective and sensitive detection of Zn2+ and DNA. The probe L achieved a detection limit of 3.8 nM for Zn2+, which is lower than the acceptable level of Zn2+ in living cells. The probe L displayed high selectivity toward Zn2+ over other interference metal ions and amino acids. Moreover, the probe L displayed low cytotoxicity and good cell permeability, indicating its potential for detecting and bio-imaging of Zn2+. In addition, the probe L-Zn2+ exhibited enhanced fluorescence signal for DNA detection through the metal-coordination interaction between Zn2+ and DNA. The enhanced signal is higher than that of the classical ethidium bromide probe. The experiments in aqueous media verified the feasibility of applying probe L in real samples.