Digital light processing of photoresponsive and programmable hydrogels

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Light-mediated hydrogel manipulation is valuable but challenging with vat photopolymerization.
• Existing methods risk consuming photoresponsive groups during printing.

Purpose of the Study:

• To develop a facile strategy for 3D printing photoresponsive hydrogels using digital light processing (DLP).
• To enable post-printing programming of hydrogel properties without compromising photoresponsive functionalities.

Main Methods:

• Combines short light exposure for shape setting with dark polymerization to complete macromer reactions.
• Utilizes photoinitiator-free reactions (tetrazole-alkene click, dithiolane ring-opening, o-nitrobenzyl cleavage) for post-printing programming.
• Employs single- or multiphoton light for precise hydrogel modification.

Main Results:

• Successfully 3D printed hydrogels with preserved photoresponsive groups.
• Demonstrated post-printing photofunctionalization, photostiffening, and photosoftening.
• Achieved applications including ligand patterning for cell guidance, 4D shape morphing, and microscale channel construction.

Conclusions:

• This approach provides highly tunable 3D-printed photoresponsive hydrogels.
• Offers versatile platform for soft matter applications requiring precise light-mediated control.