Switchable charge transport path via a potassium ions promoted conformational change of G-quadruplex probe monolayer

This communication describes a potassium ions promoted switchable charge transport path via a G-quadruplex probe monolayer. Guanine-rich (G-rich) segments are known to form specific four-stranded helical conformation (G-quadruplex) in the presence of K⁺ via intramolecular hydrogen bonds between guanines. In the absence of K⁺, this G-rich oligonucleotide is in a loosely random-coil like state and this conformational change is reversible. This conform switchable G-rich probe monolayer provide a switchable charge transport path for the oxidation of Fe (CN)₆^{4 -}. The K⁺ promoted charge transport switch were monitored by cyclic voltammetry and square-wave voltammetry (SWV).