Light-Programmable Polyester Networks with Movable Cross-Links for On-Demand Enzymatic Degradation

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Materials

Background:

• Integrating mechanical toughness with on-demand degradability is a key challenge in materials science.
• Sustainable polymers require innovative design strategies for controlled degradation.

Purpose of the Study:

• To present a photoresponsive polyester with light-regulated enzymatic degradation.
• To demonstrate a molecular-coverage-based design rule for reconciling material toughness and degradability.

Main Methods:

• Synthesized a polyester backbone with photoisomerizable trans-stilbene (tSti) units and triacetylated gamma-cyclodextrin (TAcγCD) inclusion complexes.
• Utilized UV-A and UV-C irradiation to induce reversible trans-cis isomerization of tSti units, controlling cyclodextrin ring positioning.
• Assessed lipase-catalyzed degradation rates in response to light-induced conformational changes.

Main Results:

• UV irradiation reversibly altered the positioning of cyclodextrin rings along the polyester backbone.
• This repositioning switched the molecular coverage of enzyme-active ester groups, controlling degradation.
• Polyester segments were exposed in the trans state, accelerating degradation, while shielded in the cis state, suppressing it.

Conclusions:

• Controllable cyclodextrin positioning is essential for regulating polyester degradation.
• The developed photoresponsive polyester offers tunable degradation via light stimuli.
• This study provides a molecular-coverage-based design for sustainable, tough, and degradable polymers.