Synthetic
water channels were developed with an aim to replace
aquaporins for possible uses in water purification, while concurrently
retaining aquaporins’ ability to conduct highly selective superfast
water transport. Among the currently available synthetic water channel
systems, none possesses water transport properties that parallel those
of aquaporins. In this report, we present the first synthetic water
channel system with intriguing aquaproin-like features. Employing
a “sticky end”-mediated molecular strategy for constructing
abiotic water channels, we demonstrate that a 20% enlargement in angstrom-scale
pore volume could effect a remarkable enhancement in macroscopic water
transport profile by 15 folds. This gives rise to a powerful synthetic
water channel able to transport water at a speed of ∼3 ×
109 H2O s–1 channel–1 with a high rejection of NaCl and KCl. This high water permeability,
which is about 50% of aquaporin Z’s capacity, makes channel 1 the fastest among the existing synthetic water channels
with high selectivity.
Modularly tunable monopeptidic scaffold enables rapid and combinatorial evolution of a halogen bond-mediated highly active chloride channel, exhibiting an excellent anticancer activity toward human breast cancer.
We
report here a unique ion-fishing mechanism as an alternative
to conventional carrier or channel mechanisms for mediating highly
efficient and exceptionally selective transmembrane K+ flux.
The molecular framework, underlying the fishing mechanism and comprising
a fishing rod, a fishing line and a fishing bait/hook, is simple yet
modularly modifiable. This feature enables rapid construction of a
series of molecular ion fishers with distinctively different ion transport
patterns. While more efficient ion transports are generally achieved
by using 18-crown-6 as the fishing bait/hook, ion transport selectivity
(K+/Na+) critically depends on the length of
the fishing line, with the most selective MF6-C14 exhibiting
exceptionally high selectivity (K+/Na+ = 18)
and high activity (EC
50 = 1.1 mol % relative
to lipid).
The outstanding capacity of aquaporins (AQPs) for mediating highly selective superfast water transport 1-7 has inspired recent development of supramolecular monovalent ion-excluding artificial water channels (AWCs). AWC-based bioinspired membranes are proposed for desalination, water purification, and other separations applications [8][9][10][11][12][13][14][15][16][17][18] . While some recent progress has been made in synthesizing AWCs that approach the water permeability and ion selectivity of AQPs, a hallmark feature of AQPshigh water transport while excluding protons has not been reproduced. We report on a class of biomimetic, helically folded pore-forming polymeric foldamers, that can serve as long sought-after highly selective ultrafast water-conducting channels exceeding those of AQPs (1.1 × 10 10 H2O molecules/s for AQP1 7 ), with high water over monovalent ion transport selectivity (~10 8 water molecules over Clion) conferred by the modularly tunable hydrophobicity of the interior pore surface. The best-performing AWC reported here delivers water transport at an exceptionally high rate, 2.5 times that of AQP1, while concurrently rejecting salts (NaCl and KCl) and even protons.
Reported herein is a series of pore‐containing polymeric nanotubes based on a hydrogen‐bonded hydrazide backbone. Nanotubes of suitable lengths, possessing a hollow cavity of about a 6.5 Å diameter, mediate highly efficient transport of diverse types of anions, rather than cations, across lipid membranes. The reported polymer channel, having an average molecular weight of 18.2 kDa and 3.6 nm in helical height, exhibits the highest anion‐transport activities for iodide (EC50=0.042 μm or 0.028 mol % relative to lipid), whcih is transported 10 times more efficiently than chlorides (EC50=0.47 μm). Notably, even in cholesterol‐rich environment, iodide transport activity remains high with an EC50 of 0.37 μm. 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.
A cascade reaction-based colorimetric and fluorescent probe for selective fluoride ion detection is reported. The probe displays a fast response (t1/2 = 2.41 min) and 550-fold fluorescence enhancement during sensing of fluoride ions. Application of the probe in live cell imaging is demonstrated.
We describe here a unique family of pore-forming anion-transporting peptides possessing a single-amino-acid-derived peptidic backbone that is the shortest among natural and synthetic pore-forming peptides. These monopeptides with built-in H-bonding capacity self-assemble into an H-bonded 1D columnar structure, presenting three types of exteriorly arranged hydrophobic side chains that closely mimic the overall topology of an α-helix. Dynamic interactions among these side chains and membrane lipids proceed in a way likely similar to how α-helix bundle is formed. This subsequently enables oligomerization of these rod-like structures to form ring-shaped ensembles of varying sizes with a pore size of smaller than 1.0 nm in diameter but sufficiently large for transporting anions across the membrane. The intrinsic high modularity in the backbone further allows rapid tuning in side chains for combinatorial optimization of channel's ion-transport activity, culminating in the discovery of an exceptionally active anion-transporting monopeptide 6L10 with an EC of 0.10 μM for nitrate anions.
This study reports the formation of self-assembled transmembrane anion channels by small-molecule fumaramides. Such artificial ion channel formation was confirmed by ion transport across liposomes and by planar bilayer conductance measurements. The geometry-optimized model of the channel and Cl ion selectivity within the channel lumen was also illustrated.
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