Optical Gating of Photosensitive Synthetic Ion Channels

4-oxo-4-(pyren-4-ylmethoxy) butanoic acid is used as a photolabile protecting group to show the optical gating of nanofluidic devices based on synthetic ion channels. The inner surface of the channels is decorated with monolayers of photolabile hydrophobic molecules that can be removed by irradiation, which leads to the generation of hydrophilic groups. This process can be exploited in the UV-light-triggered permselective transport of ionic species in aqueous solution through the channels. The optical gating of a single conical nanochannel and multichannel polymeric membranes is characterised experimentally and theoretically by means of currentvoltage and selective permeation measurements, respectively. It is anticipated that the integration of nanostructures into multifunctional devices is feasible and can readily find applications in light-induced controlled release, sensing, and information processing.