A highly sensitive fluorescent probe for bioimaging zinc ion in living cells and zebrafish models

Abstract

Zn²⁺ plays fundamental roles in cellular metabolism and apoptosis, as well as neurotransmission. However, how to fast detect Zn²⁺ in biology is still challenging and meaningful. In this study, we rationally synthesized a simple OFF–ON fluorescent probe for fast detection of Zn²⁺ based on intramolecular charge transfer and chelation-enhanced fluorescence. Addition of Zn²⁺ into the probe induced a significant fluorescence enhancement with a bathochromic shift of 55 nm. Moreover, the probe demonstrated excellent sensitivity (detection limit = 0.072 μM) and outstanding selectivity toward Zn²⁺ and an ultra-fast response rate of two seconds. The recognition mechanism of the probe toward Zn²⁺ was fully confirmed by HRMS and ¹H NMR spectra, as well as TDDFT calculations. Furthermore, the probe could rapidly visualize Zn²⁺ in living cells and zebrafish models in bioimaging experiments with low cytotoxicity and good biocompatibility.