Transient Formation of Supramolecular Transmembrane Ion Channel via Carbodiimide-Driven Reaction Cycle

The functions of natural proteins are often regulated by chemical reaction cycles that involve minimal chemical structural changes. Inspired by such elegant biological systems, we have developed a synthetic amphiphilic dicarboxylic acid that undergoes a transient conversion to its corresponding anhydride via a carbodiimide-driven reaction cycle. The repeatability of this cycle was confirmed both in aqueous solution and within lipid bilayer membranes using ¹H NMR spectroscopy, mass spectrometry, and electronic absorption spectroscopy. Furthermore, current recordings revealed the transient formation of supramolecular transmembrane ion channels driven by this reaction cycle. This study demonstrates the dynamic and reversible regulation of ion permeation activity in an artificial system through a chemical reaction cycle involving a minimal chemical structural change–only 1.5% (w/w) of the molecular weight–between the dicarboxylic acid and anhydride.