Bioinspired Self-Gating Nanofluidic Devices for Autonomous and Periodic Ion Transport and Cargo Release

The biochemical oscillatory reaction induced self-gating process of biological ion channels is essential to life processes, characterized as autonomous, continuous, and periodic. However, few synthetic nanochannel systems can achieve such excellent self-gating property. Their gating properties work greatly depending on the frequent addition of reactants or the supply of external stimuli. Herein, a novel bioinspired self-gating nanofluidic device that can transport mass in a continuous and periodic manner is reported. This self-gating device is constructed by using a fully closed-system pH oscillator to control the gating processes of the artificial proton-gated nanochannels. With cyclic oscillation of protons inside the nanochannel induced by the oscillatory chemical reactions of the pH oscillator, surface charge density and polarity of the nanochannels can be self-regulated, resulting in an autonomous and periodic switching of the nanochannel conductance between high and low states as well as the selectivity between cation selective and anion selective states. Moreover, by using Rhodamine B and Ruthenium(II) compound as the cationic cargoes, periodic release of these charged molecules is also observed. Therefore, this work opens up a new avenue to build self-gating nanofluidic devices, which may not only act as ion oscillators, but potentially find applications in controlled-release fields as well.