Controlling Water Flow through a Synthetic Nanopore with Permeable Cations

Area of Science:

• Nanotechnology
• Biomimetic Engineering
• Materials Science

Background:

• Intense interest exists in synthetic nanopores mimicking biological water channels.
• Existing synthetic channels lack regulated water transport, a key feature of natural channels.
• Current synthetic water channels possess hydrophobic lumens.

Purpose of the Study:

• To design and characterize a self-assembling synthetic nanopore with regulated water transport.
• To investigate the mechanism of ion-mediated water flow modulation.
• To provide a proof-of-concept for controllable synthetic water channels.

Main Methods:

• Self-assembly of macrocyclic molecules into a hybrid hydrophilic/hydrophobic nanopore.
• Stopped-flow kinetic assays to measure water transport rates.
• All-atom molecular dynamics simulations to elucidate the transport mechanism.

Main Results:

• The synthetic nanopore exhibits ion-regulated water transport.
• Water flow is dependent on alkali metal cation size, showing a non-monotonic relationship.
• Water transport ranges from negligible (with sodium ions) to rates comparable to aquaporin 1 (without cations).

Conclusions:

• Cation binding within the hybrid pore modulates water flow.
• This work offers insights into high-flux water transport through sub-nanometer pores.
• A new paradigm for designing controllable synthetic water channels is established.