Supersensitive Oxidation-Responsive Biodegradable PEG Hydrogels for Glucose-Triggered Insulin Delivery

Area of Science:

• Materials Science
• Biomedical Engineering
• Polymer Chemistry

Background:

• Reactive oxygen species (ROS)-responsive polymers and hydrogels are intelligent materials with potential in physiological and pathological processes.
• Existing ROS-responsive hydrogels often suffer from low sensitivity, slow response, instability, and poor mechanical strength.

Purpose of the Study:

• To fabricate novel oxidation-responsive degradable hydrogels with enhanced sensitivity and responsiveness.
• To develop a glucose-responsive insulin delivery platform utilizing enzymatic conversion of glucose to hydrogen peroxide (H2O2).

Main Methods:

• Fabrication of hydrogels via redox-initiated radical polymerization of a 4-arm-poly(ethylene glycol) (PEG) macromonomer with H2O2-cleavable linkers.
• Encapsulation of biomacromolecules like insulin and glucose oxidase (GOx).
• Preparation of nanogels using inverse emulsion polymerization.

Main Results:

• The developed macroscopic hydrogels exhibit good cytocompatibility, moderate mechanical strength, and rapid response to low concentrations of H2O2.
• The hydrogels effectively encapsulate biomacromolecules, forming a glucose-responsive insulin delivery system.
• Disparate degradation modes (bulk vs. surface erosion) were observed for the hydrogels triggered by H2O2 and glucose, respectively.
• Nanogels demonstrated significantly faster degradation rates compared to macroscopic hydrogels, even at pathologically relevant H2O2 concentrations.

Conclusions:

• The novel PEG-based hydrogels offer a sensitive and fast-responsive platform for ROS-triggered applications.
• The glucose-responsive system provides a promising approach for targeted insulin delivery.
• The tunable degradation properties of hydrogels and nanogels open avenues for advanced biomedical applications.