Imide Cyclophane Assemblies Enable Aquaporin-Like Water Transport

Area of Science:

• Supramolecular Chemistry
• Biomimetic Materials Science
• Membrane Technology

Background:

• Artificial water channels (AWCs) aim to replicate natural aquaporins for applications like water purification.
• Achieving both high water permeability and perfect ion selectivity simultaneously in AWCs remains a significant challenge.
• Current biomimetic channels often struggle to match the efficiency and selectivity of biological counterparts.

Purpose of the Study:

• To design and synthesize self-assembled artificial water channels (AWCs) that emulate the structure and function of natural aquaporins.
• To investigate the water transport rate and ion selectivity of these novel AWCs.
• To establish a supramolecular platform for developing high-performance biomimetic membranes.

Main Methods:

• Synthesis of an imide cyclophane macrocycle (macrocycle 1).
• Single-crystal X-ray diffraction analysis to determine the channel's internal dimensions and constriction.
• Measurement of single-channel water transport rates and selectivity against NaCl, KCl, and protons.

Main Results:

• Macrocycle 1 self-assembles into AWCs with a narrow constriction (3.5 Å × 6.3 Å) mimicking aquaporin-1's selectivity filter.
• The assembled channel ((1)₄) achieved a high single-channel water transport rate (3.9 × 10⁹ H₂O/s), reaching 36% of AQP1's efficiency.
• Demonstrated complete exclusion of NaCl, KCl, and protons, indicating perfect selectivity.

Conclusions:

• A bottom-up supramolecular approach can effectively emulate the key structural features and functions of natural aquaporins.
• The developed imide cyclophane-based AWCs represent a significant advancement in biomimetic channel performance.
• This work provides a promising platform for designing next-generation biomimetic membranes for desalination, water purification, and potential therapeutic applications.