Bulk pH-Responsive DNA Quadruplex Hydrogels Prepared by Liquid-Phase, Large-Scale DNA Synthesis

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Supramolecular Chemistry

Background:

• Development of advanced hydrogels with tunable properties is crucial for biomedical applications.
• Biocompatible materials like oligodeoxynucleotides (ODN) and polyethylene glycol (PEG) are widely used in drug delivery and tissue engineering.
• pH-responsive materials are desirable for controlled release applications.

Purpose of the Study:

• To synthesize and characterize a novel pH-responsive hydrogel biomaterial.
• To explore the potential of DNA quadruplexes (i-motifs) as triggers for hydrogel formation and stability.
• To investigate the impact of conjugate structure on hydrogel properties.

Main Methods:

• Synthesis of dC5-PEG conjugates via liquid-phase DNA synthesis and phosphoramidite chemistry.
• Preparation of hydrogels using dC5-PEG conjugates as macromonomers.
• Characterization of hydrogel properties, including stability, stiffness, and rheology.
• Investigation of i-motif formation as a trigger for hydrogelation.

Main Results:

• Successfully prepared stable and stiff pH-responsive hydrogels from dC5-PEG conjugates.
• Demonstrated that hydrogel formation and stability are triggered by DNA i-motif quadruplex formation.
• Observed significantly enhanced thermal stabilities and nonlinearly improved rheological properties due to crosslinking and topological entanglement.

Conclusions:

• A novel, biocompatible, pH-responsive hydrogel was developed using ODN and PEG.
• The DNA i-motif structure effectively triggers hydrogel formation and enhances material properties.
• The findings suggest potential applications in areas requiring controlled material responses to pH changes.