Résumé
Proton transport is crucial for cellular energy, and synthetic systems having the ability to control this process offer promising applications in drug development and cancer treatment. Herein we report a unique light-responsive proton/water transport system using self-assembled acylhydrazone-imidazole channels with tunable activity via E-Z isomerization. Three channel-forming molecules with varying alkyl chain were synthesized namely 1a (C4), 1b (C8) and 1c (C12). The photoswitching behaviour of the molecule was confirmed by UV-Vis spectroscopy within the liposome. The crystallographic analysis revealed that the E-isomer forms a H-bonded proton transport pathway mediated by water molecules. Patch clamp assays confirmed proton channel formation for 1a with a transport rate of 2.18 × 10⁷ H⁺/s/channel and high proton selectivity over other ions. Ion transport assays with EYPC-LUVs entrapped with HPTS and NaCl revealed complete rejection of external cations and anions. The compounds demonstrated significant proton transport when combined with valinomycin, indicating transmembrane proton transport for 1a-c. Upon irradiation at 310 nm, all derivatives showed increased proton transport rates, which subsequently decreased after exposure to 365 nm, confirming the photo-responsive behaviour of the system. A similar trend was observed in water transport, where the single-channel permeability of 1a increased from 6.5×10 6 to 3.5×10⁷ water molecules/s/channel upon switching from the E to Z isomers, then decreased to 1.8×10⁷ after reverting to the E conformer. Molecular simulation confirmed that stable supramolecular porous water crystal patches may form, featuring multivalent water H-bonding to acylhydrazone and imidazole units that serve as water-cluster relays within the channel.