Secondary Active Ion Transport Driven by a Lipophilicity Gated Compartmentalised Chemical Reaction

Active ion transport sustains cellular homeostasis by coupling chemical reactions to ion pumping across membranes. In nature, this coupling is achieved by complex protein pumps and transporters that convert chemical energy into transmembrane electrochemical gradients. Replicating such complex behaviour using synthetic systems remains a major challenge. Here we show that a compartmentalised chemical reaction can drive secondary active ion transport across lipid bilayers. The efficiency and lifetime of gradient formation are programmed by compound lipophilicity, revealing a precursor/product permeability asymmetry that converts reactivity into directional chemical work. Coupling this reactiongenerated proton gradient to synthetic ionophores enables uphill transport of chloride, sodium and calcium ions. Finally, incorporation of a photo-switchable molecular machine-like ion relay allows repeated cycles of chemical gradient generation and light-triggered ion pumping. These results establish reaction-driven, gated active transport in synthetic vesicles and provide design principles for chemically fuelled membrane systems that emulate key features of living cells.