Diels-Alder Click-Cross-Linked Hydrogels with Increased Reactivity Enable 3D Cell Encapsulation

Area of Science:

• Biomaterials Science
• Chemical Engineering
• Cell Biology

Background:

• Engineered hydrogels are crucial for 3D cell culture, mimicking native tissue environments.
• Previous Diels-Alder hydrogels required acidic pH, preventing viable cell encapsulation.
• Hyaluronan-furan and bis-maleimide polyethylene glycol were used in prior syntheses.

Purpose of the Study:

• To develop hydrogels that gel at physiological pH for viable cell encapsulation.
• To accelerate Diels-Alder click-cross-linking chemistry for hydrogel formation.
• To investigate the mechanism behind enhanced Diels-Alder reactivity.

Main Methods:

• Replaced hyaluronan-furan with hyaluronan-methylfuran to accelerate reaction kinetics.
• Synthesized click-cross-linked hydrogels via Diels-Alder chemistry.
• Utilized computational analysis to study reaction mechanisms.
• Demonstrated hydrogel utility with 3D culture of five cancer cell lines.

Main Results:

• New hydrogels successfully gelled at physiological pH.
• Viable cancer cell encapsulation was achieved in 3D cultures.
• Hyaluronan-methylfuran accelerated Diels-Alder cycloaddition.
• Computational analysis revealed transition state geometry and hydrogen bonding contribute to rate enhancement.

Conclusions:

• The novel hydrogel system enables efficient cell encapsulation at physiological pH.
• This click-cross-linking strategy is a versatile platform for bioconjugation and tissue engineering.
• The findings advance 3D cell culture models and biomaterial development.