Injectable poly(γ-glutamic acid)-based biodegradable hydrogels with tunable gelation rate and mechanical strength

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Regenerative Medicine

Background:

• Polypeptide-based hydrogels are promising for therapeutics and regenerative medicine.
• Challenges exist in creating injectable hydrogels with rapid gelation and controlled stiffness for clinical use.

Purpose of the Study:

• To develop injectable poly(γ-glutamic acid) (PGA)-based hydrogels with tunable properties.
• To investigate the combined effects of enzymatic crosslinking and Diels-Alder (DA) reactions on hydrogel performance.
• To assess the potential of these hydrogels for drug delivery and tissue engineering.

Main Methods:

• Constructed hydrogels using furfurylamine and tyramine-modified PGA (PGA-Fa-Tyr) and dimaleimide poly(ethylene glycol) (MAL-PEG-MAL).
• Employed a dual crosslinking strategy involving enzymatic crosslinking and Diels-Alder (DA) reaction.
• Controlled gelation time and mechanical properties by adjusting hydrogen peroxide (H2O2) concentration and reactant molar ratios.

Main Results:

• Achieved rapid hydrogel gelation within 10-95 seconds, controllable via H2O2 concentration.
• Demonstrated significantly enhanced compressive stress and strain due to the DA reaction, indicating improved toughness.
• Showcased tunable mechanical strength, swelling ratio, pore size, and degradation behavior.
• Confirmed sustained release of encapsulated bovine serum albumin.

Conclusions:

• Developed a facile strategy for creating injectable, tunable polypeptide-based hydrogels.
• The dual crosslinking approach enhances mechanical properties and imparts toughening effects.
• These hydrogels show significant potential for biomedical applications, including tissue engineering and controlled drug delivery.