We report herein a series of pore-containing polymeric nanotubes based on an H-bonded hydrazide backbone. Nanotubes of suitable lengths, possessing a hollow cavity of ~ 6.5 Å in diameter, are found to mediate highly efficient transport of diverse types of anions, rather than cations, across the lipid membrane. Polymer channel 1a, having an averaged molecular weight of 18.2 KDa and 3.6 nm in helical height, exhibits the highest anion transport activities with iodide (EC50 = 0.042 micromolar or 0.028 mol % relative to lipid) being transported 10 times more efficiently than chlorides (EC50 = 0.47 micromolar). Notably, even in the cholesterol-rich environment, iodide transport activity still remains high with EC50 of 0.37 micromolar. Molecular dynamics simulation studies confirm that the channel is highly selective for anions and that such anion selectivity arises from a positive electrostatic potential of the central lumen rendered by the interior-pointing methyl groups.
