Sticking Together: Injectable Granular Hydrogels with Increased Functionality via Dynamic Covalent Inter-Particle...

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Regenerative Medicine

Background:

• Granular hydrogels are microporous, injectable biomaterials with applications in regenerative medicine, 3D printing, and drug delivery.
• Conventional granular hydrogels often exhibit poor mechanical properties due to weak inter-microgel interactions.
• Existing methods for enhancing mechanical integrity, such as covalent crosslinking, can compromise injectability and material processing.

Purpose of the Study:

• To develop a hyaluronic acid (HA)-based granular hydrogel with enhanced mechanical integrity and injectability.
• To utilize dynamic covalent chemistry for inter-particle crosslinking in granular hydrogels.
• To explore the application of these novel hydrogels in 3D printing and cell invasion studies.

Main Methods:

• Fabrication of microgels from norbornene-modified HA via extrusion fragmentation.
• Functionalization of microgels with aldehyde or hydrazide groups.
• Formation of adhesive granular hydrogels through jamming of functionalized microgels, utilizing dynamic hydrazone bonds for crosslinking.

Main Results:

• The developed granular hydrogels exhibit enhanced mechanical integrity and shape stability compared to controls.
• The dynamic hydrazone bonds ensure the injectability of the hydrogels.
• 3D printed structures using these hydrogels demonstrate stability without post-processing.
• In vitro studies show that the adhesive granular hydrogels support cell invasion.

Conclusions:

• Dynamic covalent inter-particle crosslinking is an effective strategy to improve injectable granular hydrogels.
• The developed HA granular hydrogels offer a promising platform for advanced biomedical applications.
• This approach overcomes limitations of traditional crosslinking methods, enabling versatile material processing and improved performance.