Optical gating of photosensitive synthetic ion channels

Abstract

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 current-voltage 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. Synthetic ion channels modified with photosensitive moieties exhibit UV light-controlled ionic transport. Upon UV light irradiation the inner environment of the nanochannel is switched from a hydrophobic nonconducting (off) state to a hydrophilic conducting (on) state, allowing for the permselective transport of ionic species. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.