Transport of water across cell membranes is a fundamental
process
for important biological functions. Herein, we focused our research
on a new type of symmetrical saccharide rim-functionalized pillar[5]arene
(PA-S) artificial water channels with variable pore structures. To
point out the versatility of PA-S channels, we systematically varied
the nature of anchoring/gate keepers d-mannoside, d-mannuronic acid, or sialic acid H-bonding groups on lateral pillar[5]arene
(PA) arms, known as good membrane adhesives, to best describe the
influence of the chemical structure on their transport activity. The
control of hydrophobic membrane binding–hydrophilic water binding
balance is an important feature influencing the channels’ structuration
and efficiency for a proper insertion into bilayer membranes. The
glycosylated PA channels’ transport performances were assessed
in lipid bilayer membranes, and the channels were able to transport
water at high rates (∼106–107 waters/s/channel
within 1 order of magnitude as for aquaporins), serving as selective
proton railways with total Na+ and K+ rejection.
Molecular simulation substantiates the idea that the PAs can generate
supramolecular pores, featuring hydrophilic carbohydrate gate-keepers
that serve as water–sponge relays at the channel entrance,
effectively absorbing and redirecting water within the channel. The
present channels may be regarded as a rare biomimetic example of artificial
channels presenting proton vs cation transport selectivity performances.