A cyanine dye probe for K⁺ detection based on DNA construction of G-quadruplex

Potassium ion (K⁺) plays an important role in the maintenance of cellular biological process for human health. Thus, the detection of K⁺ is very important. Here, based on the interaction between thiamonomethinecyanine dye and G-quadruplex formation sequence (PW17), K⁺ detection spectrum was characterized by UV-Vis spectrometry. The single-stranded sequence of PW17 can fold into G-quadruplex in the presence of K⁺. PW17 can induce a dimer-to-monomer transition of the absorption spectrum of cyanine dyes. This method shows high specificity against some other alkali cations, even at high concentrations of Na⁺. Further, this detection strategy can realize the detection of K⁺ in tap water.