Conformation-Adaptive Crown Ether-Polyimides as Superfast and Exceptionally Selective Artificial Na⁺ Channels

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Chemical Engineering

Background:

• Developing artificial ion channels with high sodium (Na+) permeability and selectivity is challenging due to inherent trade-offs.
• Existing synthetic systems face a performance ceiling, limiting their practical applications.

Purpose of the Study:

• To overcome the permeability-selectivity trade-off in artificial ion channels.
• To design a novel adaptive system for efficient and selective Na+ transport.

Main Methods:

• An adaptive design strategy using a flexible polyimide backbone functionalized with 15-crown-5 ionophores.
• Tunable alkyl linkers (Cn H2n+1, n = 8-16) were employed to modify the backbone.
• Investigated conformational plasticity for dynamic ion coordination during transport.

Main Results:

• The best-performing transporter (4) achieved a Na+ conductance of 48.9 pS, surpassing gramicidin A's K+ transport by twofold.
• A record Na+/K+ selectivity of 37.8 was obtained.
• Demonstrated efficient Na+ permeation through adaptive mechanisms.

Conclusions:

• The developed adaptive design strategy establishes a new benchmark for synthetic ion transporters.
• This work opens avenues for advanced biomimetic membranes and novel therapeutic applications.
• The flexible architecture enables dynamic ion coordination for enhanced transport properties.