A dynamic and self-crosslinked polysaccharide hydrogel with autonomous self-healing ability

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Natural polymeric hydrogels offer promising biomedical applications due to their biocompatibility and biodegradability.
• Self-healing hydrogels can recover functionality and structure after damage, enhancing their utility.
• Developing efficient and robust self-healing hydrogels from natural sources remains a key challenge.

Purpose of the Study:

• To develop a novel self-healable polymeric hydrogel using two natural polymers: acrylamide-modified chitin (AMC) and oxidized alginate.
• To investigate the mechanism of self-crosslinking and the factors influencing self-healing capability.
• To explore the potential of this hydrogel as a soft template for inorganic material repair.

Main Methods:

• Synthesized acrylamide-modified chitin (AMC) and oxidized alginate.
• Fabricated self-crosslinked hydrogels via Schiff base dynamic covalent linkages between AMC and oxidized alginate.
• Investigated self-healing efficiency by assessing recovery of mechanical properties and structure after damage.
• Explored the effect of polymer ratio and pH on self-healing.
• Demonstrated freeze-drying for storage and rehydration for activation of self-healing.
• Utilized the hydrogel as a template for hydroxyapatite repair.

Main Results:

• A self-healable hydrogel was successfully fabricated through the dynamic covalent Schiff base reaction between AMC and oxidized alginate.
• Self-healing capability was dependent on the molar ratio of AMC to oxidized alginate and the surrounding pH.
• The hydrogel exhibited significant self-healing, with complete recovery observed under optimal conditions, allowing for substantial stretching.
• The self-healing ability could be stored via freeze-drying and reactivated upon rehydration.
• The hydrogel demonstrated utility as a soft template to guide the repair of hydroxyapatite.

Conclusions:

• A novel, self-healable hydrogel based on natural polysaccharides (AMC and oxidized alginate) was developed.
• The hydrogel's self-healing properties are tunable and can be stored and reactivated, offering practical advantages.
• The material shows potential for diverse biomedical applications, including acting as a template for biomaterial repair.