A ratiometric fluorescent sensor with a large Stokes shift for imaging zinc ions in living cells

The ratiometric fluorescent sensor FQ1 based on furoquinoline has been designed and synthesized, and not only exhibits a large Stokes shift of 199 nm in a mixture of C2H5OH-H2O (v/v = 8 : 2, 10 mM Tris-HCl, pH = 7.3), but can selectively detect zinc ions in the presence of competing metal ions with a red-shift of 75 nm; moreover, cell stain experiments show that FQ1 can readily reveal a change in intracellular Zn2+.