Artificial, switchable K+-gated ion channels based on flow-through titania-nanotube arrays.

In the present work, we demonstrated a novel type of artificial K(+)-gated ion channels based on titania nanotubes loaded with Au nanoparticles and G-rich DNA composite structure. K(+) promoted conformational change of G-rich DNA from flexible chain to rigid quadruplex, which provided a blocking effect for the transport of anions such as Fe(CN)(6)(4-) and other molecules through the channels in TiO(2) nanotubes. This fabricated permselective membrane using K(+) as a trigger may set light to the field of biosensing, drug-release, ion exchange membrane and so on.