Hydrolytically Degradable Microgels with Tunable Mechanical Properties Modulate the Host Immune Response.

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Tissue Engineering

Background:

• Hydrogel microparticles (microgels) offer advantages for therapeutic delivery, including modularity, injectability, and tissue integration.
• Current microgel fabrication methods offer diverse chemistries, but the impact of degradability on in vivo tissue responses is not fully understood.

Purpose of the Study:

• To develop a facile method for synthesizing microgels with tunable degradation kinetics.
• To investigate the effects of microgel degradation on in vivo tissue responses and immune modulation.

Main Methods:

• Synthesis of maleimide-functionalized poly(ethylene-glycol) microgels using droplet microfluidics.
• Crosslinking with thiol-terminated, ester-containing molecules to control degradation rates.
• Evaluation of microgel mechanics, degradation in aqueous media, cytocompatibility, and in vivo tissue responses.

Main Results:

• Tunable microgel mechanics achieved by varying degradable and nondegradable crosslinker ratios.
• Microgels exhibit time-dependent degradation (weeks in vivo) with byproduct cytocompatibility.
• In vivo studies revealed a dynamic type-1 immune response, modulated by microgel degradation properties.

Conclusions:

• A hydrolytic microgel platform with tunable degradation kinetics was successfully developed.
• The platform allows for adaptation to specific host tissue immune responses.
• These findings support the potential of these microgels for advanced therapeutic delivery applications.