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

A new "turn-on" fluorescent probe (PTAHN) based on a biological purine derivative for detecting Zn(2+)was designed, synthesized and characterized. ThePTAHNexhibited remarkable selectivity and rapid response toward Zn2+, as well as obvious fluorescence enhancement upon combining with Zn(2+)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 mu M). Meanwhile, an obvious color change can be visually observed by the naked eye betweenPTAHNandPTAHN-Zn2+. What's more, the sensing mechanism ofPTAHNtoward Zn(2+)was supported by the Job's plot,H-1 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.