Synthetic Ion Channel Formed by Multiblock Amphiphile with Anisotropic Dual-Stimuli-Responsiveness

Transmembrane proteins within biological membranes exhibit varieties of important functions that are vital for many cellular activities, and the development of their synthetic mimetics allows for deep understanding in related biological events. Inspired by the structures and functions of natural ion channels that can respond to multiple stimuli in an anisotropic manner, we developed multiblock amphiphile V in this study. When V was incorporated into the lipid bilayer membranes, V formed a supramolecular ion channel whose ion transport property was controllable by the polarity and amplitude of the applied voltage. Microscopic emission spectroscopy revealed that V changed its molecular conformation in response to the applied voltage. Furthermore, the ion transport property of V could be reversibly switched by the addition of (R)-propranolol, an aromatic amine known as an antiarrhythmic agent, followed by the addition of β-cyclodextrin for its removal. The highly regulated orientation of V allowed for an anisotropic dual-stimuli-responsiveness for the first time as a synthetic ion channel.