A cofactor mediated supramolecular oligo-adenine triplex for reprogrammable macroscopic hydrogel assembly.

Area of Science:

• Supramolecular Chemistry
• DNA Nanotechnology
• Materials Science

Background:

• Noncanonical DNA structures offer versatile applications in the DNA toolbox.
• Low-molecular-weight cofactors can mediate the formation of these structures.
• Cyanuric acid (CA) is a cofactor with thymine-like edges.

Purpose of the Study:

• To investigate the use of cyanuric acid (CA) as a cofactor for assembling adenine-rich DNA strands.
• To explore the pH-dependent structural transitions of the resulting DNA-cofactor complex.
• To utilize this system for macroscopic, reprogrammable object assembly.

Main Methods:

• Assembly of adenine-rich DNA strands with cyanuric acid (CA) under specific pH conditions.
• Characterization of the parallel noncanonical A-CA triplex formation via Watson-Crick and Hoogsteen interactions.
• Demonstration of pH-triggered reversible assembly and disassembly of hydrogel constructs.

Main Results:

• A stable, parallel noncanonical A-CA triplex is formed below the pKa of CA (pH 6.9).
• The A-CA triplex dissociates into single strands and free CA at higher pH, showing full reversibility.
• The A-CA triplex successfully functions as a crosslinker for assembling macroscopic hydrogel cubes (5x5x5 mm).
• Controlled assembly and disassembly into various configurations (square, line, T-shape) were achieved by adjusting pH.

Conclusions:

• Cyanuric acid (CA) facilitates the formation of pH-responsive DNA-based supramolecular assemblies.
• This strategy enables cost-effective, recyclable, and stimuli-responsive hydrogel modification and construction.
• The approach provides a foundation for developing adaptive supramolecular systems for diverse applications.