Ruthenium-Crosslinked Hydrogels with Rapid, Visible-Light Degradation

Area of Science:

• Materials Science
• Biomaterials Engineering
• Photochemistry

Background:

• Photoresponsive molecules offer spatiotemporal control in soft materials for applications like targeted delivery.
• Existing methods often suffer from slow reaction kinetics and utilize ultraviolet light, limiting their practical use.

Purpose of the Study:

• To develop a novel photoactive crosslinker for rapid hydrogel degradation under visible light.
• To create a hydrogel system for efficient encapsulation and controlled release of protein cargo.
• To explore the fabrication of microgels from the developed photoactive hydrogel system.

Main Methods:

• Synthesis of a novel photoactive crosslinker, Ru(bipyridine)2(3-pyridinaldehyde)2 (RuAldehyde).
• Formation of hydrogels by reacting RuAldehyde with hydrazide-functionalized hyaluronic acid.
• Degradation of hydrogels and release of encapsulated protein cargo (TEM1 β-lactamase) using visible light (400-500 nm).
• Fabrication of microgels using a microfluidic platform.

Main Results:

• Visible light irradiation rapidly degraded the Ru-hyaluronic acid hydrogels within seconds to minutes.
• The hydrogel system successfully encapsulated and facilitated the photorelease of TEM1 β-lactamase.
• Ru-hydrogels were successfully processed into microgels via microfluidics, expanding potential applications.

Conclusions:

• The novel RuAldehyde crosslinker enables rapid, visible-light-triggered hydrogel degradation.
• This system provides a promising platform for controlled protein delivery and the development of advanced soft materials.
• The ability to form microgels further broadens the utility of these photoresponsive materials.