1.D.162. The Multiblock Amphiphile Nanopore (MA-NP) Family
Sato et al. 2021 developed a series of multiblock amphiphiles (MAs) composed of a repetitive sequence of flexible hydrophilic oligo(ethylene glycol) chains and rigid hydrophobic oligo(phenylene-ethynylene) units. These MAs can be incorporated into the hydrophobic layer of lipid bilayer membranes and adopt folded conformations, with their hydrophobic units stacked in a face-to-face configuration. The folded MAs can self-assemble within the membranes and form supramolecular nanopores that can transport ions across the membranes. They developed MAs incorporating sterically bulky groups within their hydrophobic units and demonstrated that their transmembrane ion transport properties could be controlled via mechanical forces applied to the membranes. Some MAs incorporated phosphate ester groups that functioned as ligand-binding sites at the boundary between hydrophilic and hydrophobic units and found that these MAs exhibited transmembrane ion transport properties upon binding with aromatic amine ligands, even within the biological membranes of living cells. They further modified the hydrophobic units of the MAs with fluorine atoms and demonstrated voltage-responsive transmembrane ion transport properties. These molecular design principles were extended to the development of transmembrane anion transporters whose transport mechanism was studied by all-atom molecular dynamics simulations (Sato et al. 2021).