A selective purine-based fluorescent chemosensor for the “naked-eye” detection of zinc ions (Zn2+): applications in live cell imaging and test strips

Abstract

A new “turn-on” fluorescent probe (PTAHN) based on a biological purine derivative for detecting Zn²⁺ was designed, synthesized and characterized. The PTAHN exhibited remarkable selectivity and rapid response toward Zn²⁺, as well as obvious fluorescence enhancement upon combining with Zn²⁺ in a HEPES buffer system at pH 7.4. The limit of detection (LOD) for Zn²⁺ (61.6 nM) is much lower than the WHO standards (76.0 μM). Meanwhile, an obvious color change can be visually observed by the naked eye between PTAHN and PTAHN–Zn²⁺. What's more, the sensing mechanism of PTAHN toward Zn²⁺ was supported by the Job's plot, ¹H NMR and density functional theory (DFT) studies. Interestingly, the novel probe is cell-permeable and can be successfully used for the detection of intracellular zinc ions in living HepG-2 cells.